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Xue, S.

Publications and source records attributed to Xue, S..

At least 37 records · Page 2Linked to original sources

Turnover of RNA-binding Proteins and MicroRNAs by intrinsically disordered region-directed ZSWIM8 ubiquitin ligase during brain development

Widely present in mammalian proteomes, intrinsically disordered regions (IDRs) in proteins play important biological functions by conferring structural flexibility and mediating biomolecular interactions. IDR-containing proteins, including many RNA-binding proteins (RBPs), are prone to misfolding and aggregation and must be constantly monitored. Here we show that the conserved ZSWIM8-type Cullin-RING ubiquitin ligase (CRLZSWIM8) is a master regulator of such proteins during brain development. ZSWIM8 selects its substrates via an IDR-dependent mechanism, and deletion of ZSWIM8 causes aberrant accumulation of numerous RBPs including AGO2 and ELAV1 in neonatal brains. Furthermore, AGO2 ubiquitination by ZSWIM8 is triggered by microRNA binding, leading to target-directed microRNA degradation (TDMD) of MiR7. Dysregulation of MiR7 in the absence of ZSWIM8 results in defects in oligodendrocyte maturation and functions. Together, our findings have demonstrated that, by utilizing variable target-recognition strategies, ZSWIM8 controls the abundance of conformationally flexible RBPs and miRNA metabolism that are essential for brain development. TeaserA conserved ubiquitin ligase controls the quality of disordered proteins to ensure brain development.

developmental biology↗

Development of a qPCR assay and a LAMP assay for Verticillium longisporum detection and a triplex qPCR assay for simultaneous detection of V. longisporum, Leptosphaeria biglobosa and L. maculans from canola samples

Verticillium wilt, Verticillium stem striping, and Verticillium stripe, are common disease names that all denote infection caused by Verticillium longisporum, on canola, or other Brassica crops. In this study, a quantitative PCR (qPCR) assay and a loop-mediated isothermal amplification (LAMP) assay were developed for the detection of V. longisporum from canola stem samples. Both assays are specific to V. longisporum at the species level and ubiquitous at the strain level. The low limit for positive detection of the two assays is 1 pg fungal DNA in a 20-{micro} L reaction or 1,400 fungal cells in 100-mg plant tissue. The qPCR assay was combined with the duplex qPCR assay for the two blackleg pathogens, Leptosphaeria biglobosa and L. maculans to constitute a triplex qPCR system for simultaneous detection of all three pathogens. The usefulness of this triplex qPCR system was verified on canola samples collected from various locations in Alberta, Canada. Using this triplex qPCR system, V. longisporum was detected from one sample, while the two blackleg pathogens were detected at higher frequencies. Since it is sometimes difficult to differentiate Verticillium stripe and blackleg on Alberta canola samples based on visual symptoms, the triplex qPCR system is an important tool for the detection of V. longisporum, especially when its presence is masked or obscured by symptoms of blackleg.

microbiology↗

Determination and characterization of papillomaviurs and parvovirus causing mass mortality of Chinese tongue sole (Cynoglossus semilaevis) in China

Chinese tongue sole (Cynoglossus semilaevis) is one of the representative species in flatfish aquaculture in China. In recent years, massive mortality of farmed Chinese tongue soles occurred in Tianjin, China. The causative pathogens were determined as Cynoglossus semilaevis papillomavirus (CsPaV) and parvovirus (CsPV) by electron microscopy, virus isolation, experimental challenge, histopathological analysis, genome sequencing, fluorescence In situ hybridization (FISH) and epidemiology investigation. Electron microscopy showed large numbers of spherical non-enveloped virus particles presenting in liver, kidney, spleen, gill and heart of the diseased fish. The viruses were isolated and propagated in flounder gill cells (FG) and induced a typical cytopathic effect (CPE). The cumulative mortality reached 100% at 8 dpi by intraperitoneal injection. The complete genome of CsPaV and CsPV was 5939 bp and 3663 bp in size respectively, and both viral genomes shared no nucleotide sequence similarity with other viruses. The CsPaV contained seven predicated protein coding regions (E1, E2, L2, L1a, L1b, sORF1 and sORF2) and CsPV contained three predicated protein coding regions (NS1, VP and ORF3). Phylogenetic analysis basing on L1 and NS1 protein sequences revealed that CsPaV and CsPV are novel members belonging to new genus in Papillomaviridae and Parvoviridae family. FISH results showed positive signals in spleen and kidney tissues from CsPaV and CsPV infected fish and the two viruses could co-infected one cell. Epidemiological investigation showed that the two viruses cocurrented in 82.9% sampled fish and they were proved to be the pathogenic agents of the emerging disease in farmed Chinese tongue soles in China. This study represents the first report of co-infection of papillomavirus and parvovirus in farmed fish and provides a basis for further studies on prevention and treatment of the emerging viral disease, and also represents clues to elucidate the the mechanisms of viruses co-infection and evolution of viruses. Author summaryChinese tongue sole is a valuable fish kept in marincultures. Outbreak of an emerging disease caused massive mortality and resulted in significant economic loss. The pathogenic agent remains unknown. In this study, we identified papillomavirus (CsPaV) and parvovirus (CsPV) from the diseased fish simultaneously, and they are proved to be novel members belonging to new genus in Papillomaviridae and Parvoviridae family. It was shown that the emerging disease was caused by co-infection with the two viruses. Viral co-infections are widespread in nature, however, studies and available data on viral co-infections in fish aquaculture are limited. Our findings represent new clues to elucidate the mechanisms of viruses co-infection and evolution of viruses, and moreover, the present study provide a solution for the control of emerging viral diseases in Chinese tongue sole.

microbiology↗

Featural representation and internal noise underlie the eccentricity effect in contrast sensitivity

Human visual performance for basic visual dimensions (e.g., contrast sensitivity and acuity) peaks at the fovea and decreases with eccentricity. The eccentricity effect is related to the larger surface area of the visual cortex corresponding to the fovea, but it is unknown if differential feature tuning contributes to this eccentricity effect. Here, we investigated two system-level computations underlying the eccentricity effect: featural representation (tuning) and internal noise. Observers (both sexes) detected a Gabor embedded in filtered white noise which appeared at the fovea or one of four perifoveal locations. We used psychophysical reverse correlation to estimate the weights assigned by the visual system to a range of orientations and spatial frequencies (SFs) in noisy stimuli, which are conventionally interpreted as perceptual sensitivity to the corresponding features. We found higher sensitivity to task-relevant orientations and SFs at the fovea than the perifovea, and no difference in selectivity for either orientation or SF. Concurrently, we measured response consistency using a double-pass method, which allowed us to infer the level of internal noise by implementing a noisy observer model. We found lower internal noise at the fovea than perifovea. Finally, individual variability in contrast sensitivity correlated with sensitivity to and selectivity for task-relevant features as well as with internal noise. Moreover, the behavioral eccentricity effect mainly reflects the foveal advantage in orientation sensitivity compared to other computations. These findings suggest that the eccentricity effect stems from a better representation of task-relevant features and lower internal noise at the fovea than at the perifovea. SignificancePerformance in many visual tasks worsens with eccentricity. Many studies attribute this eccentricity effect to retinal and cortical factors, like higher cone density and a larger cortical surface area representing the foveal than peripheral locations. We investigated whether system-level computations for task-relevant visual features also underlie this eccentricity effect. Measuring contrast sensitivity in visual noise, we showed that the fovea better represents task-relevant orientation and spatial frequency and has lower internal noise than the perifovea, and that individual variability in these two computations correlates with that in performance. These findings reveal that both representations of these basic visual features and internal noise underlie the difference in performance with eccentricity.

neuroscience↗

Sinorhizobium meliloti FcrX coordinates cell cycle and division during free-living growth and symbiosis

Sinorhizobium meliloti is a soil bacterium that establishes a symbiosis within root nodules of legumes (Medicago sativa, for example) where it fixes atmospheric nitrogen into ammonia and obtains in return carbon sources and other nutrients. In this symbiosis, S. meliloti undergoes a drastic cellular change leading to a terminal differentiated form (called bacteroid) characterized by genome endoreduplication, increase of cell size and high membrane permeability. The bacterial cell cycle (mis)regulation is at the heart of this differentiation process. In free-living cells, the master regulator CtrA ensures the progression of cell cycle by activating cell division (controlled by the tubulin-like protein FtsZ) and simultaneously inhibiting supernumerary DNA replication, while on the other hand the downregulation of CtrA and FtsZ is essential for bacteroid differentiation during symbiosis, preventing endosymbiont division and permitting genome endoreduplication. Little is known in S. meliloti about regulators of CtrA and FtsZ, as well as the processes that control bacteroid development. Here, we combine cell biology, biochemistry and bacterial genetics approaches to understand the function(s) of FcrX, a new factor that controls both CtrA and FtsZ, in free-living growth and in symbiosis. Depletion of the essential gene fcrX led to abnormally high levels of FtsZ and CtrA and minicell formation. Using multiple complementary techniques, we showed that FcrX is able to interact physically with FtsZ and CtrA. Moreover, its transcription is controlled by CtrA itself and displays an oscillatory pattern in the cell cycle. We further showed that, despite a weak homology with FliJ-like proteins, only FcrX proteins from closely-related species are able to complement S. meliloti fcrX function. Finally, deregulation of FcrX showed abnormal symbiotic behaviors in plants suggesting a putative role of this factor during bacteroid differentiation. In conclusion, FcrX is the first known cell cycle regulator that acts directly on both, CtrA and FtsZ, thereby controlling cell cycle, division and symbiotic differentiation.

microbiology↗

Comparative analysis of chloroplast genome between wild and cultivated Rehmannia glutinosa Libosch.

Rehmanniae radix, as a tonic Chinese medicine, has a good therapeutic effect on cardiovascular and cerebrovascular diseases and central nervous system diseases, and has a good development prospect in the international market. R.glutinosa Libosch has a large number of source varieties, and the wild and cultivated varieties are different types of R.glutinosa Libosch. There has been a lot of controversy in the formulation of scientific names for wild and cultivated types of R.glutinosa Libosch. In order to learn more about the genetic information of wild R.glutinosa Libosch and explore the phylogenetic relationship between wild R.glutinosa Libosch and cultivated R.glutinosa Libosch. In the current study, we constructed and annotated a complete circular chloroplast genome of wild R.glutinosa Libosch. The chloroplast genome of wild R.glutinosa Libosch. is 153,678 bp in length, including two inverted repeat (IR) regions of 25,759 bp, separated by a large single copy (LSC) region of 84,544 bp and a small single copy (SSC) region of 17,616 bp. The GC content of whole chloroplast genome is 37.9%. The genome contains 133 different genes, including 88 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Among them, 23 genes contained introns, 50 SSR loci and 49 long repeats were found by Microsatellite scan, and codon use showed obvious A, T base preference. Nine variation regions were screened by mVISTA analysis and combined with DnaSP analysis, and psaJ-rpl33 was finally identified as a region with high variation, which could be used as a candidate DNA barcode for later interspecific identification of R.glutinosa Libosch.. Neighbor-joining method phylogenomic analysis showed that wild R.glutinosa Libosch. formed a monophyletic group, and was sister to other groups of R.glutinosa Libosch.The results of this study revealed the chloroplast genome information of wild R.glutinosa Libosch in detail, and found the genetic information difference between wild and cultivated R.glutinosa Libosch. which laid the foundation for the variety identification, genetic engineering, biosynthesis and other studies.

molecular biology↗

Fortuitous Somatic Mutations during Antibody Evolution Endow Broad Neutralization against SARS-CoV-2 Omicron Variants

Striking antibody evasion by emerging circulating SARS-CoV-2 variants drives the identification of broadly neutralizing antibodies (bNAbs). However, how a bNAb acquires increased neutralization breadth during antibody evolution is still elusive. Here, we identified a clonally-related antibody family from a convalescent individual. One of the members, XG005, exhibited potent and broad neutralizing activities against SARS-CoV-2 variants, while the other members showed significant reductions in neutralization breadth and potency, especially against the Omicron sublineages. Structural analysis visualizing the XG005-Omicron spike binding interface revealed how crucial somatic mutations endowed XG005 with greater neutralization potency and breadth. A single administration of XG005 with extended half-life, reduced antibody-dependent enhancement (ADE) effect, and increased antibody product quality, exhibited a high therapeutic efficacy in BA.2- and BA.5-challenged mice. Our results provided a natural example to show the importance of somatic hypermutation during antibody evolution for SARS-CoV-2 neutralization breadth and potency.

immunology↗

Nipsnap1- A Regulatory Factor Required for Long-Term Maintenance of Non-Shivering Thermogenesis

The molecular activation of non-shivering thermogenesis (NST) has strong potential to combat obesity and metabolic disease. However, the mechanisms surrounding the maintenance of NST once it is fully activated, remain unexplored. Here, we present 4-Nitrophenylphosphatase Domain and Non-Neuronal SNAP25-Like 1 (Nipsnap1) as a critical regulator of long-term thermogenic maintenance in brown adipose tissue (BAT). Nipsnap1 localizes to the mitochondrial matrix and increases its transcript and protein levels in response to both chronic cold and {beta}3 adrenergic signaling. Through the generation of BAT-specific Nipsnap1 knockout mice (N1-KO), we show that these mice are unable to sustain activated energy expenditure and fail to protect their body temperature in the face of an extended cold challenge. Mechanistically, we demonstrate that Nipsnap1 integrates with lipid metabolism and BAT-specific ablation of Nipsnap1 leads to severe defects in {beta}-oxidation capacity. Our findings identify Nipsnap1 as a potent regulator of long-term NST maintenance.

molecular biology↗

Rsc3K, a SMV resistance gene localized on chromosome 2 in soybean cv. Kefeng No.1, interacts with virulence determinant P3

Soybean mosaic virus (SMV) is one of the most devastating viral pathogens in Glycine max (L.) Merr (soybean). Twenty-two SMV strains (SC1-SC22) isolated in China were identified based on their responses to ten soybean cultivars. By using the F2-derived F3 (F2:3) and recombinant inbred line (RIL) populations of resistant Soybean cultivar (cv.) Kefeng No.1 x susceptible cv. Nannong 1138-2, we localized the gene mediating resistant to SMV-SC3 strain to a 90 kb interval on chromosome 2 in Kefeng No.1. Bean pod mottle virus (BPMV)-induced gene silencing (VIGS) were used to study the gene function of candidate genes in the mapping interval and revealed that an recombinant gene, later named as Rsc3K, caused by internal deletion of a genomic DNA frag ement in Kefeng No.1, is the resistant gene to SMV-SC3. By shuffling genes between avirulent isolate SC3 and avirulent SMV isolate 1129, we found that P3 is the virulence determinant causing resistance on Kefeng No.1. We showed the interaction between Rsc3K and P3 by the yeast two-hybrid (Y2H) and bimolecular fluorescent complementation (BiFC) assays. In conclusion, this study demonstrated that Rsc3K plays a crucial role in resistance of Kefeng No.1 to SMV-SC3 by direct interaction with viral protein P3. HighlightRsc3K resistant to SMV-SC3 by interacting with P3.

molecular biology↗

Differential Network Analysis of Longitudinal Gene Expression in Response to Perturbations.

Understanding changes in gene expression under the effects of a perturbation is a key goal of systems biology. A powerful approach to address this goal uses gene networks and describes the perturbations effects as a rewiring of each genes connections. This approach is known as differential network (DN) analysis. Here, we used DNs to analyze RNA-sequencing time series datasets, focusing on expression changes: (i) In the saliva of a human subject after vaccination with a pneumococcal vaccine (PPSV23), and (ii) in B cells treated ex vivo with a monoclonal antibody drug (Rituximab). Using network community detection, we revealed the collective behavior of clusters of genes, and detected communities of genes based on their longitudinal behavior, and corresponding pathway activations. We identified biological pathways consistent with the mechanism of action of the vaccine and with Rituximabs targets. The approach may be useful in drug development by providing an effective analysis of expressing changes in response to a drug.

bioinformatics↗

Phase separation on cell surface: a mechanism of basic fibroblast growth factor signal transduction with heparan sulphate

Liquid-liquid phase separation (LLPS) driven by weak, multivalent interactions among biomolecules is an important means of cellular compartmentation and plays a central role in cellular processes including stress resistance, RNA processing and other cellular activities. Coordination of the condensates and inner membrane was recently revealed, mediating intracellular processes like cell signalling and cargo trafficking. Intracellular LLPS has been observed extensively in vivo, whereas LLPS in extracellular compartments has not been reported under physiological conditions. Here we show, for the first time, that basic fibroblast growth factor (bFGF) undergoes LLPS on the cell surface by interacting with heparan sulphate proteoglycans (HSPG) and the phase transition is required for effective downstream signalling. The condensation is driven by multivalent interactions between bFGF and sulpho-groups on heparan sulphate (HS), and dimerization and oligomerization of bFGF promote the LLPS process. Compared with free bFGF, phase separated bFGF with HS showed higher thermo stability, providing a potential mechanism for the preservation of bFGF activity. Furthermore, we have found that downstream signalling is triggered by phase separation of a ternary complex formed by bFGF, HSPGs and FGFR on cell surface. Our results revealed a molecular mechanism that HS can serve as a platform to promote extracellular proteins like bFGF to condensate on outer membrane, consequently coordinating the signal transduction activities. This novel finding expands the horizons of phase separation in vivo, providing a new dimension on how HSPG may regulate extracellular protein behaviour and cell signalling.

biochemistry↗

riboviz 2: A flexible and robust ribosome profiling data analysis and visualization workflow

MotivationRibosome profiling, or Ribo-seq, is the state of the art method for quantifying protein synthesis in living cells. Computational analysis of Ribo-seq data remains challenging due to the complexity of the procedure, as well as variations introduced for specific organisms or specialized analyses. Many bioinformatic pipelines have been developed, but these pipelines have key limitations in terms of functionality or usability. ResultsWe present riboviz 2, an updated riboviz package, for the comprehensive transcript-centric analysis and visualization of Ribo-seq data. riboviz 2 includes an analysis workflow built on the Nextflow workflow management system, combining freely available software with custom code. The package is extensively documented and provides example configuration files for organisms spanning the domains of life. riboviz 2 is distinguished by clear separation of concerns between annotation and analysis: prior to a run, the user chooses a transcriptome in FASTA format, paired with annotation for the CDS locations in GFF3 format. The user is empowered to choose the relevant transcriptome for their biological question, or to run alternative analyses that address distinct questions. riboviz 2 has been extensively tested on various library preparation strategies, including multiplexed samples. riboviz 2 is flexible and uses open, documented file formats, allowing users to integrate new analyses with the pipeline. Availabilityriboviz 2 is freely available at github.com/riboviz/riboviz. Supplementary information

bioinformatics↗

SMCHD1 variants may induce variegated expression in Facio Scapulo Humeral Dystophy and Bosma Arhinia and microphtalmia syndrome

An expanding number of genetic syndromes are linked to mutations in genes encoding factors that guide chromatin organization. Recently, distinct genetic syndromes have been linked to mutations in the SMCHD1 gene. However, the function of this non-canonical SMC protein remains partly defined in Human tissues. To address this question, we determined its epi-signature in type 2 Facio Scapulo Humeral Dystrophy (FSHD2) and Bosma Arhinia and Microphtalmia Syndrome (BAMS) linked to heterozygous mutations in this gene. By combining RNA-Seq, DNA methylation profiling and ChIP-Seq, we showed that SMCHD1 regulates repressed chromatin but also cis-regulatory elements and enhancers. Our results emphasize dual functions for SMCHD1, in chromatin compaction, chromatin insulation and gene regulation with variable outcomes and targets depending on tissues. We propose that altered DNA methylation and long-range chromatin organization at a number of loci required for development and tissue differentiation, trigger variegated gene expression in rare genetic diseases linked to heterozygous SMCHD1 mutations.

genetics↗

SMCHD1 has separable roles in chromatin architecture and gene silencing that could be targeted in disease

The interplay between 3D chromatin architecture and gene silencing is incompletely understood. Here, we report a novel point mutation in the non-canonical SMC protein SMCHD1 that enhances its silencing capacity at endogenous developmental targets and at the facioscapulohumeral muscular dystrophy associated macro-array, D4Z4. Heightened SMCHD1 silencing perturbs developmental Hox gene activation, causing a homeotic transformation in mice. Paradoxically, the mutant SMCHD1 appears to enhance insulation against another epigenetic regulator complex, PRC2, while depleting long range chromatin interactions akin to what is observed in the absence of SMCHD1. These data suggest that SMCHD1s role in long range chromatin interactions is not directly linked to gene silencing or insulating the chromatin, refining the model for how the different levels of SMCHD1-mediated chromatin regulation interact to bring about gene silencing in normal development and disease.

molecular biology↗

An amiRNA screen uncovers redundant CBF & ERF34/35 transcription factors that differentially regulate arsenite and cadmium responses

Arsenic stress causes rapid transcriptional responses in plants. However, transcriptional regulators of arsenic-induced gene expression in plants remain less well known. To date, forward genetic screens have proven limited for dissecting arsenic response mechanisms. We hypothesized that this may be due to the extensive genetic redundancy present in plant genomes. To overcome this limitation, we pursued a forward genetics screen for arsenite tolerance using a randomized library of plants expressing >2,000 artificial microRNAs (amiRNAs). This library was designed to knock-down diverse combinations of homologous gene family members within sub-clades of transcription factor and transporter gene families. We identified six transformant lines showing an altered response to arsenite in root growth assays. Further characterization of an amiRNA line targeting closely homologous CBF and ERF transcription factors show that the CBF1,2 and 3 transcription factors negatively regulate arsenite sensitivity. Furthermore, the ERF34 and ERF35 transcription factors are required for cadmium resistance. Generation of CRISPR lines, higher-order T-DNA mutants, and gene expression analyses, further support our findings. These ERF transcription factors differentially regulate arsenite sensitivity and cadmium tolerance.

plant biology↗

Longitudinal Saliva Omics Responses to Immune Perturbation: A Case Study

Saliva omics, a rapidly developing field for non-invasive diagnostics, may be utilized for monitoring very young or elderly populations, as well as individuals in remote locations. In this study, multiple saliva omics from an individual were monitored over 100 timepoints, over three periods involving: (i) hourly sampling over 24 hours without intervention, (ii) hourly sampling over 24 hours including immune system activation using the standard 23-valent pneumococcal polysaccharide vaccine, (iii) daily sampling for 33 days profiling the post-vaccination response. At each timepoint total saliva transcriptome and proteome were profiled, and salivary extracellular vesicles were derived, from which small-RNA sequencing was used to determine RNA, miRNA, piRNA and bacterial RNA components. The two 24-hour periods were used in a paired analysis to reveal vaccination responses. Temporal trends were classified and collective behavior revealed broad immune-responses captured in saliva, both at the innate as well as the adaptive response time frames.

genomics↗

Single cell atlas of trisomy 21 cerebral cortex

Down syndrome (DS) is one of the most common human birth defects caused by trisomy 21 (T21), leading to a variety of cognitive impairments. The cellular composition of human brain has been explored using single cell RNA sequencing in both physiological and pathological conditions. However, the cellular heterogeneity of human brain with chromosome aneuploidy is largely unknown. Here, we profiled the transcriptome of 36046 cells in cerebral cortex of T21 human fetus, covering frontal lobe, parietal lobe, occipital lobe and temporal lobe. Intriguingly, we detected several genes positively associated with neurons maturation was dysregulated in T21 frontal cortex (HIC2, POU2F2, ZGLP1 and FOXK1). To share, explore and utilized the data resources of T21 cerebral cortex, we developed a comprehensive platform named T21atlas, composing of two functional modules (T21cluster and T21talk). Overall, our study provides, as far as we know, the first single cell atlas for T21 cerebral cortex, which could promote our understanding of the molecular mechanism of DS at an unprecedented resolution and could potentially facilitate the development of novel clinical therapeutics against T21.

neuroscience↗

Single cell RNA sequencing reveals cellular diversity of trisomy 21 retina

Retina is a crucial tissue for the capturing and processing of light stimulus. Characterization of the retina at single cell level is essential for the understanding of its biological functions. A variety of abnormalities in terms of morphology and function were reported in T21 retina. To evaluate the effects of chromosome aneuploidy on retina development, we characterized single cell transcriptional profiles of a T21 fetus and performed comprehensive bioinformatic analyses. Our data revealed the diversity and heterogeneity of cellular compositions in T21 retina. In total, we identified seven major cell types, and detected several subtypes within each cell type, followed by the detection of corresponding molecular markers including previously reported ones and a series of novel markers. Our analyses identified extensive communication networks between distinct cellular types, among which a few ligand-receptor interactions were associated with the development of retina and immunoregulatory interactions. Taken together, our data provided the first single cell transcriptome profile for human T21 retina which facilitates our understanding on the dosage effects of chromosome 21 on the development of retina.

cell biology↗