Biology subjects

Ma, Y.

Publications and source records attributed to Ma, Y..

At least 379 records · Page 21Linked to original sources

bioRxiv2021

Genome-wide in vivo screen of circulating tumor cells identifies SLIT2 as a regulator of metastasis

Circulating tumor cells (CTCs) break free from primary tumors and travel through the bloodstream and lymphatic system to seed metastatic tumors, which are the major cause of death from cancer. The identification of the major genetic factors that enhance production and persistence of CTCs in the bloodstream at a whole genome level would enable more comprehensive molecular mechanisms of metastasis to be elucidated and the identification of novel therapeutic targets, but this remains a challenging task due to the heterogeneity and extreme rarity of CTCs. Here, we describe the first in vivo genome-wide CRISPR KO screen using CTCs directly isolated from a mouse xenograft. This screen elucidated SLIT2 - a gene encoding a secreted protein acting as a cellular migration cue - as the most significantly represented gene knockout in the CTC population. SLIT2 knockout cells are highly metastatic with hypermigratory and mesenchymal phenotype. Reduced expression of SLIT2 is observed in human tumors, indicating its role as a negative modulator of tumor progression and metastasis.

cancer biology↗

bioRxiv2021

Lupus Gut Microbiota Transplants Cause Autoimmunity and Inflammation

BackgroundThe etiology of systemic lupus erythematosus (SLE) is multifactorial. Recently, growing evidence suggests that the microbiota plays a role in SLE, yet whether gut microbiota participates in the development of SLE remains largely unknown. To investigate this issue, we carried out 16s rDNA sequencing analyses in a cohort of 18 female un-treated active SLE patients and 7 female healthy controls, and performed fecal microbiota transplantation from patients and healthy controls to germ-free mice. ResultsCompared to the healthy controls, we found no significant different microbial diversity but some significantly different species in SLE patients including Turicibacter genus and other 5 species. Fecal transfer from SLE patients to germ free (GF) C57BL/6 mice caused GF mice to develop a series of lupus-like phenotyptic features, which including an increased serum autoimmune antibodies, and imbalanced cytokines, altered distribution of immune cells in mucosal and peripheral immune response, and upregulated expression of genes related to SLE in recipient mice that received SLE fecal microbiota transplantation (FMT). Moreover, the metabolism of histidine was significantly altered in GF mice treated with SLE patient feces, as compared to those which received healthy fecal transplants. ConclusionsOverall, our results describe a causal role of aberrant gut microbiota in contributing to the pathogenesis of SLE. The interplay of gut microbial and histidine metabolism may be one of the mechanisms intertwined with autoimmune activation in SLE.

immunology↗

bioRxiv2021

Optimal dynamic incentive scheduling for Hawk-Dove evolutionary games

The Hawk-Dove mathematical game offers a paradigm of the trade-offs associated with aggressive and passive behaviors. When two (or more) populations of players (animals, insect populations, countries in military conflict, economic competitors, microbial communities, populations of co-evolving tumor cells, or reinforcement learners adopting different strategies) compete, their success or failure can be measured by their frequency in the population (successful behavior is reinforced, unsuccessful behavior is not), and the system is governed by the replicator dynamical system. We develop a time-dependent optimal-adaptive control theory for this nonlinear dynamical system in which the payoffs of the Hawk-Dove payoff matrix are dynamically altered (dynamic incentives) to produce (bang-bang) control schedules that (i) maximize the aggressive population at the end of time T, and (ii) minimize the aggressive population at the end of time T. These two distinct time-dependent strategies produce upper and lower bounds on the outcomes from all strategies since they represent two extremizers of the cost function using the Pontryagin maximum (minimum) principle. We extend the results forward to times nT (n = 1, ..., 5) in an adaptive way that uses the optimal value at the end of time nT to produce the new schedule for time (n + 1)T. Two special schedules and initial conditions are identified that produce absolute maximizers and minimizers over an arbitrary number of cycles for 0 [≤] T [≤] 3. For T > 3, our optimum schedules can drive either population to extinction or fixation. The method described can be used to produce optimal dynamic incentive schedules for many different applications in which the 2 x 2 replicator dynamics is used as a governing model.

evolutionary biology↗

bioRxiv2021

Visualizing conformational space of functional biomolecular complexes by deep manifold learning

The cellular functions are executed by biological macromolecular complexes in nonequilibrium dynamic processes, which exhibit a vast diversity of conformational states. Solving conformational continuum of important biomolecular complexes at atomic level is essential to understand their functional mechanisms and to guide structure-based drug discovery. Here we introduce a deep learning framework, named AlphaCryo4D, which enables atomic-level cryogenic electron microscopy reconstructions of conformational continuum. AlphaCryo4D integrates 3D deep residual learning with manifold embedding of energy landscapes, which simultaneously improves 3D classification accuracy and reconstruction resolution via an energy-based particle-voting algorithm. By applications of this approach to analyze five experimental datasets, we demonstrate its generality in breaking resolution barrier of visualizing dynamic components of functional complexes, in choreographing continuous inter-subunit motions and in exploring their hidden conformational space. Our approach expands the realm of structural ensemble determination to the nonequilibrium regime at atomic level, thus potentially transforming biomedical research and therapeutic development.

bioinformatics↗

bioRxiv2021

Early megakaryocyte lineage-committed progenitors in adult mouse bone marrow

Hematopoietic stem cells (HSCs) have been considered to progressively lose their self-renewal and differentiation potentials prior to the commitment to each blood lineage. However, recent studies have suggested that megakaryocyte progenitors are generated at the level of HSCs. In this study, we newly identified early megakaryocyte lineage-committed progenitors (MgPs) in CD201-CD48- cells and CD48+ cells separated from the CD150+CD34-Kit+Sca-1+Lin- HSC population of the bone marrow in C57BL/6 mice. Single-cell transplantation and single-cell colony assay showed that MgPs, unlike platelet-biased HSCs, had little repopulating potential in vivo, but formed larger megakaryocyte colonies in vitro (on average eight megakaryocytes per colony) than did previously reported megakaryocyte progenitors (MkPs). Single-cell RNA-sequencing supported that these MgPs lie between HSCs and MkPs along the megakaryocyte differentiation pathway. Single-cell colony assay and single-cell RT-PCR analysis suggested the coexpression of CD41 and Pf4 is associated with megakaryocyte colony-forming activity. Single-cell colony assay of a small number of cells generated from single HSCs in culture suggested that MgPs are not direct progeny of HSCs. In this study, we propose a differentiation model in which HSCs give rise to MkPs through MgPs.

cell biology↗

bioRxiv2021

Cytoplasmic labile iron accumulates in aging stem cells perturbing a key rheostat for identity control

Bone marrow resident and rarely dividing haematopoietic stem cells (HSC) harbour an extensive self-renewal capacity to sustain life-long blood formation;1-5 albeit their function declines during ageing.6, 7 Various molecular mechanisms confer stem cell identity, ensure long-term maintenance and are known to be deregulated in aged stem cells.8, 9 How these programs are coordinated, particularly during cell division, and what triggers their ageing-associated dysfunction has been unknown. Here, we demonstrate that HSC, containing the lowest amount of cytoplasmic chelatable iron (labile iron pool)10 among hematopoietic cells, activate a limited iron response during mitosis. Engagement of this iron homeostasis pathway elicits mobilization and {beta}-oxidation of arachidonic acid and enhances stem cell-defining transcriptional programs governed by histone acetyl transferase Tip60/KAT5. We further find an age-associated expansion of the labile iron pool, along with loss of Tip60/KAT5-dependent gene regulation to contribute to the functional decline of ageing HSC, which can be mitigated by iron chelation. Together, our work reveals cytoplasmic redox active iron as a novel rheostat in adult stem cells; it demonstrates a role for the intracellular labile iron pool in coordinating a cascade of molecular events which reinforces HSC identity during cell division and to drive stem cell ageing when perturbed. As loss of iron homeostasis is commonly observed in the elderly, we anticipate these findings to trigger further studies into understanding and therapeutic mitigation of labile iron pool-dependent stem cell dysfunction in a wide range of degenerative and malignant pathologies.

cell biology↗

bioRxiv2021

Natural interploidy hybridization among the key taxa involved in the origin of horticultural chrysanthemums

Understanding hybridization and introgression between natural plant populations can give important insights into the origins of cultivated species. Recent studies suggest differences in ploidy may not create such strong reproductive barriers as once thought, and thus studies into cultivated origins should examine all co-occurring taxa, including those with contrasting ploidy levels. Here, we characterized hybridization between Chrysanthemum indicum, Chrysanthemum vestitum and Chrysanthemum vestitum var. latifolium, the most important wild species involved in the origins of cultivated chrysanthemums. We analysed population structure of 317 Chrysanthemum accessions based on 13 microsatellite markers and sequenced chloroplast trnL-trnF for a subset of 103 Chrysanthemum accessions. We identified three distinct genetic clusters, corresponding to the three taxa. We detected 20 hybrids between species of different ploidy levels, of which 19 were between C. indicum (4x) and C. vestitum (6x) and one was between C. indicum and C. vestitum var. latifolium (6x). Fourteen hybrids between C. indicum and C. vestitum were from one of the five study sites. Chrysanthemum vestitum and C. vestitum var. latifolium share only one chloroplast haplotype. The substantially different number of hybrids between hybridizing species was likely due to different levels of reproductive isolation coupled with environmental selection against hybrids. In addition, human activities may play a role in the different patterns of hybridization among populations.

evolutionary biology↗

bioRxiv2021

Crystal structures of taxane-tubulin complexes: Implications for the mechanism of microtubule stabilization by Taxol

Paclitaxel (Taxol(R)) is a taxane and a first-line chemotherapeutic drug that stabilizes microtubules. While the interaction of paclitaxel with microtubules is well described, the current lack of high-resolution structural information on a tubulin-taxane complex precludes a comprehensive description of the binding determinants that affect the drugs mechanism of action. Here, we solved the crystal structure of the core baccatin III moiety of paclitaxel lacking the C13 side chain in complex with tubulin at 1.9 [A] resolution. Based on this information, we engineered two tailor-made taxanes with modified C13 side chains, solved their crystal structures in complex with tubulin, and analyzed their effects along with those of paclitaxel, docetaxel, and baccatin III on the microtubule lattice by X-ray fiber diffraction. We then compared high-resolution structures of ligand-bound tubulin and microtubule complexes with apo forms and used molecular dynamics simulations to understand the consequences of taxane binding to tubulin as well as to simplified protofilament and microtubule-lattice models. Our combined approach sheds light on three mechanistic questions. Firstly, taxanes bind better to microtubules as compared to unassembled tubulin due to a dual structural mechanism: Tubulin assembly is linked to a conformational reorganization of the {beta}M loop, which otherwise occludes ligand access to the taxane site, while the bulky C13 side chains preferentially recognize the microtubule-assembled over the unassembled conformational state of tubulin. Second, the occupancy of the taxane site by a ligand has no influence on the straightness of tubulin protofilaments. Finally, binding of the taxane core to the taxane site displaces the S9-S10 loop of {beta}-tubulin resulting in microtubule expansion. Our results provide detailed new insights into the mechanism of microtubule-stabilization by taxanes.

biophysics↗

bioRxiv2021

Rapid visual CRISPR assay: a naked-eye colorimetric detection method for nucleic acids based on CRISPR/Cas12a and convolutional neural network

Rapid diagnosis based on naked-eye colorimetric detection remains challenging, but it could build new capacities for molecular point-of-care testing (POCT). In this study, we evaluated the performance of 16 types of single-stranded DNA-fluorophore-quencher (ssDNA-FQ) reporters for use with CRISPR/Cas12a based visual colorimetric assays. Among them, 9 ssDNA-FQ reporters were found to be suitable for direct visual colorimetric detection, with especially very strong performance using ROX-labeled reporters. We optimized the reaction concentrations of these ssDNA-FQ reporters for naked-eye read-out of assay results (no transducing component required for visualization). Subsequently, we developed a convolutional neural network algorithm standardize and to automate the analytical colorimetric assessment of images and integrated this into the MagicEye mobile phone software. A field-deployable assay platform named RApid VIsual CRISPR (RAVI-CRISPR) based on a ROX-labeled reporter with isothermal amplification and CRISPR/Cas12a targeting was established. We deployed RAVI-CRISPR in a single tube towards an instrument-less colorimetric POCT format that requires only a portable rechargeable hand warmer for incubation. The RAVI-CRISPR was successfully used for the single-copy detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and African swine fever virus (ASFV). Our study demonstrates this novel RAVI-CRISPR system for distinguishing different pathogenic nucleic acid targets with high specificity and sensitivity as the simplest-to-date platform for rapid pen-side testing.

molecular biology↗

bioRxiv2021

WDR82-binding long non-coding RNA lncEry controls mouse erythroid differentiation and maturation

Hematopoietic differentiation is controlled by both genetic and epigenetic regulators. Long non-coding RNAs (lncRNAs) have been demonstrated to be important for normal hematopoiesis, but their function in erythropoiesis needs to be further explored. We profiled the transcriptomes of 16 murine hematopoietic cell populations by deep RNA-sequencing and identified a novel lncRNA, Gm15915, that was highly expressed in erythroid-related progenitors and erythrocytes. For this reason, we named it lncEry. We also identified a novel lncEry isoform, which was also the principal transcript that has not been reported before. LncEry depletion impaired erythropoiesis, indicating the important role of the lncRNA in regulating erythroid differentiation and maturation. Mechanistically, we found that lncEry interacted with WD repeat-containing protein 82 (WDR82) to promote the transcription of Klf1 and globin genes and thus control the early and late stages of erythropoiesis, respectively. These findings identified lncEry as an important player in the transcriptional regulation of erythropoiesis.

cell biology↗

bioRxiv2021

Regulation Network of Colorectal Cancer Specific Enhancers in Progression of Colorectal Cancer

Enhancers regulate multiple genes through higher-order chromatin structure and further affect cancer progression. Epigenetic changes in cancer cells activate several cancer specific enhancers that are silenced in normal cells. These cancer specific enhancers are potential therapeutic targets of cancer. However, functions and regulation network of colorectal cancer specific enhancers are still unknown. Here in this study, we profile colorectal cancer specific enhancers and reveal the regulation network of these enhancers by analysis of HiChIP, Hi-C and RNA-seq data. We propose the regulation network of colorectal cancer specific enhancers plays important role in progression of colorectal cancer.

genetics↗

bioRxiv2021

MPI8 is Potent Against SARS-CoV-2 by Inhibiting Dually and Selectively the SARS-CoV-2 Main Protease and the Host Cathepsin L

A number of inhibitors have been developed for the SARS-CoV-2 main protease (MPro) as potential COVID-19 medications but little is known about their selectivity. Using enzymatic assays, we characterized inhibition of TMPRSS2, furin, and cathepsins B/K/L by more than a dozen of previously developed MPro inhibitors including MPI1-9, GC376, 11a, 10-1, 10-2, and 10- 3. MPI1-9, GC376 and 11a all contain an aldehyde for the formation of a reversible covalent hemiacetal adduct with the MPro active site cysteine and 10-1, 10-2 and 10-3 contain a labile ester to exchange with the MPro active site cysteine for the formation of a thioester. Our data revealed that all these inhibitors are inert toward TMPRSS2 and furin. Diaryl esters also showed low inhibition of cathepsins. However, all aldehyde inhibitors displayed high potency in inhibiting three cathepsins. Their determined IC50 values vary from 4.1 to 380 nM for cathepsin B, 0.079 to 2.3 nM for cathepsin L, and 0.35 to 180 nM for cathepsin K. All aldehyde inhibitors showed similar inhibition levels toward cathepsin L. A cellular analysis indicated high potency of MPI5 and MPI8 in inhibiting lysosomal activity, which is probably attributed to their inhibition of cathepsins. Among all aldehyde inhibitors, MPI8 shows the best selectivity toward cathepsin L. With respect to cathepsins B and K, the selective indices are 192 and 150, respectively. MPI8 is the most potent compound among all aldehyde inhibitors in cellular MPro inhibition potency and anti-SARS-CoV-2 activity in Vero E6 cells. Cathepsin L has been demonstrated to play a critical role in the SARS-CoV-2 cell entry. By selectively inhibiting both SARS-CoV-2 MPro and the host cathepsin L, MPI8 potentiates dual inhibition effects to synergize its overall antiviral potency and efficacy. Due to its high selectivity toward cathepsin L that reduces potential toxicity toward host cells and high cellular and antiviral potency, we urge serious consideration of MPI8 for preclinical and clinical investigations for treating COVID-19.

pharmacology and toxicology↗

bioRxiv2021

Cellular Activities of SARS-CoV-2 Main Protease Inhibitors Reveal Their Unique Characteristics

As an essential enzyme of SARS-CoV-2, the pathogen of COVID-19, main protease (MPro) triggers acute toxicity to its human cell host, an effect that can be alleviated by an MPro inhibitor with cellular potency. By coupling this toxicity alleviation with the expression of an MPro-eGFP fusion protein in a human cell host for straightforward characterization with fluorescent flow cytometry, we developed an effective method that allows bulk analysis of cellular potency of MPro inhibitors. In comparison to an antiviral assay in which MPro inhibitors may target host proteases or other processes in the SARS-CoV-2 life cycle to convene strong antiviral effects, this novel assay is more advantageous in providing precise cellular MPro inhibition information for assessment and optimization of MPro inhibitors. We used this assay to analyze 30 literature reported MPro inhibitors including MPI1-9 that were newly developed aldehyde-based reversible covalent inhibitors of MPro, GC376 and 11a that are two investigational drugs undergoing clinical trials for the treatment of COVID-19 patients in United States, boceprevir, calpain inhibitor II, calpain inhibitor XII, ebselen, bepridil that is an antianginal drug with potent anti-SARS-CoV-2 activity, and chloroquine and hydroxychloroquine that were previously shown to inhibit MPro. Our results showed that most inhibitors displayed cellular potency much weaker than their potency in direct inhibition of the enzyme. Many inhibitors exhibited weak or undetectable cellular potency up to 10 M. On contrary to their strong antiviral effects, 11a, calpain inhibitor II, calpain XII, ebselen, and bepridil showed relatively weak to undetectable cellular MPro inhibition potency implicating their roles in interfering with key steps other than just the MPro catalysis in the SARS-CoV-2 life cycle to convene potent antiviral effects. characterization of these molecules on their antiviral mechanisms will likely reveal novel drug targets for COVID-19. Chloroquine and hydroxychloroquine showed close to undetectable cellular potency to inhibit MPro. Kinetic recharacterization of these two compounds rules out their possibility as MPro inhibitors. Our results also revealed that MPI5, 6, 7, and 8 have high cellular and antiviral potency with both IC50 and EC50 values respectively below 1 M. As the one with the highest cellular and antiviral potency among all tested compounds, MPI8 has a remarkable cellular MPro inhibition IC50 value of 31 nM that matches closely to its strong antiviral effect with an EC50 value of 30 nM. Given its strong cellular and antiviral potency, we cautiously suggest that MPI8 is ready for preclinical and clinical investigations for the treatment of COVID-19.

biochemistry↗

bioRxiv2021

Revealing the full biosphere structure and versatile metabolic functions in the deepest ocean sediment of the Challenger Deep

BackgroundThe full biosphere structure and functional exploration of the microbial communities of the Challenger Deep of the Mariana Trench, the deepest known hadal zone on Earth, lag far behind that of other marine realms. ResultsWe adopt a deep metagenomics approach to investigate the microbiome in the sediment of Challenger Deep, Mariana Trench. We construct 178 metagenome-assembled genomes (MAGs) representing 26 phyla, 16 of which are reported from hadal sediment for the first time. Based on the MAGs, we find the microbial community functions are marked by enrichment and prevalence of mixotrophy and facultative anaerobic metabolism. The microeukaryotic community is found to be dominated by six fungal groups that are characterized for the first time in hadal sediment to possess the assimilatory and dissimilatory nitrate/sulfate reduction, and hydrogen sulfide oxidation pathways. By metaviromic analysis, we reveal novel hadal Caudovirales clades, distinctive virus-host interactions, and specialized auxiliary metabolic genes for modulating hosts nitrogen/sulfur metabolism. The hadal microbiome is further investigated by large-scale cultivation that cataloged 1070 bacterial and 19 fungal isolates from the Challenger Deep sediment, many of which are found to be new species specialized in the hadal habitat. ConclusionOur hadal MAGs and isolates increase the diversity of the Challenger Deep sediment microbial genomes and isolates present in the public. The deep metagenomics approach fills the knowledge gaps in structure and diversity of the hadal microbiome, and provides novel insight into the ecology and metabolism of eukaryotic and viral components in the deepest biosphere on earth.

microbiology↗

bioRxiv2021

Immunological profiling of COVID-19 patients with pulmonary sequelae

Cellular immunity may be involved in organ damage and rehabilitation in patients with coronavirus disease 2019 (COVID-19). We aimed to delineate immunological features of COVID-19 patients with pulmonary sequelae (PS) one year after discharge. 50 COVID-19 survivors were recruited and classified according to radiological characteristics: 24 patients with PS and 26 patients without PS. Phenotypic and functional characteristics of immune cells were evaluated by multiparametric flow cytometry. Patients with PS had an increased proportion of natural killer (NK) cells and lower percentage of B cells compared to patients without PS. Phenotypic and functional features of T cells in patients with PS were predominated by the accumulation of CD4+ T cells secreting IL-17A, short-lived effector-like CD8+ T cells (CD27-CD62L-) and senescent T cells with excessive secretion of granzyme-B/perforin/IFN-{gamma}. NK cells were characterized by the excessive secretion of granzyme-B and perforin and the downregulation of NKP30 and NKP46; highly activated NKT and {gamma}{delta} T cells exhibited NKP30 and TIM-3 upregulation and NKB1 downregulation in patients with PS. However, immunosuppressive cells were comparable between the two groups. The interrelation of immune cells in COVID-19 was intrinsically identified, whereby T cells secreting IL-2, IL-4 and IL-17A were enriched among CD28+ and CD57-cells and cells secreting perforin/granzyme-B/IFN-{gamma}/TNF- expressed markers of terminal differentiation. CD57+NK cells, CD4+perforin+ T cells and CD8+CD27+CD62L+ T cells were identified as the independent predictors for residual lesions. Overall, our findings unveil the profound imbalance of immune landscape that may correlate with organ damage and rehabilitation in COVID-19. IMPORTANCEA considerable proportion of COVID-19 survivors have residual lung lesions, such as ground glass opacity and fiber streak shadow. To determine the relationship between host immunity and residual lung lesions, we performed an extensive analysis of immune responses in convalescent patients with COVID-19 one year after discharge. We found significant differences in immunological characteristics between patients with pulmonary sequelae and patients without pulmonary sequelae one year after discharge. Our study highlights the profound imbalance of immune landscape in the COVID-19 patients with pulmonary sequelae, characterized by the robust activation of cytotoxic T cells, NK cells and {gamma}{delta} T cells as well as the deficiencies of immunosuppressive cells. Importantly, CD57+NK cells, CD4+perforin+ T cells and CD8+CD27+CD62L+ T cells were identified as the independent predictors for residual lesions.

immunology↗

bioRxiv2021

Inducible and reversible inhibition of miRNA-mediated gene repression in vivo

Although virtually all gene networks are predicted to be controlled by miRNAs, the contribution of this important layer of gene regulation to tissue homeostasis in adult animals remains unclear. Gain and loss of function experiments have provided key insights into the specific function of individual miRNAs, but effective genetic tools to study the functional consequences of global inhibition of miRNA activity in vivo are lacking. Here we report the generation and characterization of a genetically engineered mouse strain in which miRNA-mediated gene repression can be reversibly inhibited without affecting miRNA biogenesis or abundance. We demonstrate the usefulness of this strategy by investigating the consequences of acute inhibition of miRNA function in adult animals. We find that different tissues and organs respond differently to global loss of miRNA function. While miRNA-mediated gene repression is essential for the homeostasis of the heart and the skeletal muscle, it is largely dispensable in the majority of other organs. Even in tissues where it is not required for homeostasis, such as the intestine and hematopoietic system, miRNA activity can become essential during regeneration following acute injury. These data support a model where many metazoan tissues primarily rely on miRNA function to respond to potentially pathogenic events.

molecular biology↗

bioRxiv2021

Subcellular localization of PKA catalytic subunits provides a basis for their distinct functions in the retina

PKA signaling is essential for numerous processes but the subcellular localization of specific PKA isoforms has yet to be explored comprehensively in tissues. Expression of the C{beta} protein, in particular, has not been mapped previously at the tissue level. In this study we used retina as a window into PKA signaling in the brain and characterized localization of PKA C, C{beta}, RII, and RII{beta} subunits. Each subunit presented a distinct localization pattern. C and C{beta} were localized in all tissue layers, while RII and RII{beta} were enriched in the photoreceptor cells in contrast to the cell body and retinal portion of retinal ganglion cells. Only C was observed in photoreceptor outer segments and the cilia transition zone, while C{beta} was localized primarily to mitochondria and was especially prominent in the ellipsoid of the cone cells. In contrast to C, C{beta} also never colocalized with RII or RII{beta}. Using BaseScope technology to track expression of the C{beta} isoforms we find that C{beta}4 and C{beta}4ab are prominently expressed and, therefore, likely code for mitochondrial-C{beta} proteins. Our data indicates that PKA subunits are functionally nonredundant in the retina and suggesting that C{beta} might be important for mitochondrial-associated neurodegenerative diseases previously linked to PKA dysfunction.

neuroscience↗

bioRxiv2021

Harnessing genetic diversity in the USDA pea (Pisum sativum L.) germplasm collection through genomic prediction

Phenotypic evaluation and efficient utilization of germplasm collections can be time-intensive, laborious, and expensive. However, with the plummeting costs of next-generation sequencing and the addition of genomic selection to the plant breeders toolbox, we now can more efficiently tap the genetic diversity within large germplasm collections. In this study, we applied and evaluated genomic selections potential to a set of 482 pea accessions - genotyped with 30,600 single nucleotide polymorphic (SNP) markers and phenotyped for seed yield and yield-related components - for enhancing selection of accessions from the USDA Pea Germplasm Collection. Genomic prediction models and several factors affecting predictive ability were evaluated in a series of cross-validation schemes across complex traits. Different genomic prediction models gave similar results, with predictive ability across traits ranging from 0.23 to 0.60, with no model working best across all traits. Increasing the training population size improved the predictive ability of most traits, including seed yield. Predictive abilities increased and reached a plateau with increasing number of markers presumably due to extensive linkage disequilibrium in the pea genome. Accounting for population structure effects did not significantly boost predictive ability, but we observed a slight improvement in seed yield. By applying the best genomic prediction model (e.g., RR-BLUP), we then examined the distribution of genotyped but nonphenotyped accessions and the reliability of genomic estimated breeding values (GEBV). The distribution of GEBV suggested that none of the nonphenotyped accessions were expected to perform outside the range of the phenotyped accessions. Desirable breeding values with higher reliability can be used to identify and screen favorable germplasm accessions. Expanding the training set and incorporating additional orthogonal information (e.g., transcriptomics, proteomics, metabolomics, physiological traits, etc.) into the genomic prediction framework could enhance prediction accuracy.

genomics↗