Biology subjects

Grive, K. J.

Publications and source records attributed to Grive, K. J..

5 recordsLinked to original sources

bioRxiv2026

Differential chromatin looping regulated by two GA-binding transcription factors creates an X-specific chromatin environment for dosage compensation

The mechanisms by which differential occupancy of transcription factors (TFs) at similar binding sites leads to context-specific targeting of large transcription complexes remain poorly understood. X chromosome upregulation (XCU), the most highly conserved step in dosage compensation and best studied in Drosophila, serves as a model for understanding how differential occupancy of similar TFs functions context-specifically. Sequence variation within GA-repeat motifs that accumulated on the X chromosome over evolutionary time promotes the binding of a specific GA-binding TF (CLAMP) that recruits the dosage compensation complex (DCC) while outcompeting another similar TF (GAF). However, the mechanism by which CLAMP-GAF competition drives specific targeting of the DCC to the X chromosome remains unknown. Because DCC binding sites cluster in 3D space, we combined Micro-C and Hi-ChIP to determine that CLAMP and GAF directly mediate largely mutually exclusive 3D genomic contacts. Specifically, we show that CLAMP but not GAF drives local short-range interactions that directly link high affinity DCC binding sites with active, dosage-compensated housekeeping genes. In contrast, GAF mediates interactions between transcriptionally silent insulator regions on the X chromosome spanning a wider range of genomic distances. Together, these findings demonstrate that CLAMP outcompetes GAF at active regions on the X chromosome, but not autosomes, to create an X-chromosome specific chromatin environment for dosage compensation. Overall, we provide new insight into how differential TF binding at similar binding sites drives context-specific targeting of transcription complexes.

molecular biology↗

bioRxiv2024

Immune checkpoint inhibitor treatment does not impair ovarian or endocrine function in a mouse model of triple negative breast cancer

BackgroundRepresenting 15-20% of all breast cancer cases, triple negative breast cancer (TNBC) is diagnosed more frequently in reproductive-age women and exhibits higher rates of disease metastasis and recurrence when compared with other subtypes. Few targeted treatments exist for TNBC, and many patients experience infertility and endocrine disruption as a result of frontline chemotherapy treatment. While they are a promising option for less toxic therapeutic approaches, little is known about the effects of immune checkpoint inhibitors on reproductive and endocrine function. ResultsOur findings in a syngeneic TNBC mouse model revealed that therapeutically relevant immunotherapies targeting PD-1, LAG-3, and TIM-3 had no effect on the quality and abundance of ovarian follicles, estrus cyclicity, or hormonal homeostasis. Similarly, in a tumor-free mouse model, we found that ovarian architecture, follicle abundance, estrus cyclicity, and ovulatory efficiency remain unchanged by PD-1 blockade. ConclusionsTaken together, our results suggest that immunotherapy may be a promising component of fertility-sparing therapeutic regimens for patients that wish to retain ovarian and endocrine function after cancer treatment.

cancer biology↗

bioRxiv2022

The Requirement of Ubiquitin C-Terminal Hydrolase L1 (UCHL1) in Mouse Ovarian Development and Fertility

Ubiquitin C-Terminal Hydrolase L1 (UCHL1) is a de-ubiquitinating enzyme enriched in neuronal and gonadal tissues known to regulate the cellular stores of mono-ubiquitin and protein turnover. While its function in maintaining proper motor neuron function is well-established, investigation into its role in the health and function of reproductive processes is only just beginning to be studied. Single-cell-sequencing analysis of all ovarian cells from the murine perinatal period revealed that Uchl1 is very highly expressed in the developing oocyte population, an observation which was corroborated by high levels of oocyte-enriched UCHL1 protein expression in oocytes of all stages throughout the mouse reproductive lifespan. To better understand the role UCHL1 may be playing in oocytes, we utilized a UCHL1-deficient mouse line, finding reduced number of litters, reduced litter sizes, altered folliculogenesis, morphologically abnormal oocytes, disrupted estrous cyclicity and apparent endocrine dysfunction in these animals compared to their wild-type and heterozygous littermates. These data reveal a novel role of UCHL1 in female fertility as well as overall ovarian function, and suggest a potentially essential role for the ubiquitin proteasome pathway in mediating reproductive health. Summary sentenceUbiquitin C-Terminal Hydrolase L1 (UCHL1) is required for proper ovarian folliculogenesis, estrous cyclicity, and fertility in the female mouse.

developmental biology↗

bioRxiv2021

Multiple 9-1-1 complexes promote homolog synapsis, DSB repair, and ATR signaling during mammalian meiosis

DNA damage response mechanisms have meiotic roles that ensure successful gamete formation. While completion of meiotic double-strand break (DSB) repair requires the canonical RAD9A-RAD1-HUS1 (9A-1-1) complex, mammalian meiocytes also express RAD9A and HUS1 paralogs, RAD9B and HUS1B, predicted to form alternative 9-1-1 complexes. The RAD1 subunit is shared by all predicted 9-1-1 complexes and localizes to meiotic chromosomes even in the absence of HUS1 and RAD9A. Here we report that testis-specific RAD1 disruption resulted in impaired DSB repair, germ cell depletion and infertility. Unlike Hus1 or Rad9a disruption, Rad1 loss also caused defects in homolog synapsis, ATR signaling and meiotic sex chromosome inactivation. Comprehensive testis phosphoproteomics revealed that RAD1 and ATR coordinately regulate numerous proteins involved in DSB repair, meiotic silencing, synaptonemal complex formation, and cohesion. Together, these results establish critical roles for both canonical and alternative 9-1-1 complexes in meiotic ATR activation and successful prophase I completion.

genetics↗

bioRxiv2018

Dynamic transcriptome profiles within spermatogonial and spermatocyte populations during postnatal testis maturation revealed by single-cell sequencing

Spermatogenesis is the process by which male gametes are formed from a self-renewing population of spermatogonial stem cells (SSCs) residing in the testis. SSCs represent less than 1% of the total testicular cell population, but must achieve a stable balance between self-renewal and differentiation. Once differentiation has occurred, the newly formed and highly proliferative spermatogonia must then enter the meiotic program in which DNA content is doubled, then halved twice to create haploid gametes. While much is known about the critical cellular processes that take place during the specialized cell division that is meiosis, much less is known about how the spermatocytes in the \"first-wave\" compare to those that contribute to long-term, \"steady-state\" spermatogenesis. Given the strictly-defined developmental process of spermatogenesis, this study was aimed at exploring the transcriptional profiles of developmental cell stages over the age of the animal. Using a combination of comprehensive germ cell sampling with high-resolution, single-cell-mRNA-sequencing, we have generated a reference dataset of germ cell gene expression. We show that discrete developmental stages possess significant differences in the transcriptional profiles from neonates compared to juveniles and adults. Importantly, these gene expression dynamics are also reflected at the protein level in their respective cell types. We also show differential utilization of many biological pathways with age in both spermatogonia and spermatocytes, demonstrating significantly different underlying gene regulatory programs in these cell types over the course of testis development and spermatogenic waves. This dataset represents the first unbiased sampling of spermatogonia and spermatocytes in the developing testis over developmental age, at high-resolution, single-cell depth. Not only does this analysis reveal previously unknown transcriptional dynamics of a highly transitional cell population, it has also begun to reveal critical differences in biological pathway utilization in developing spermatogonia and spermatocytes, including response to DNA damage and double-strand breaks.\n\nAuthor SummarySpermatogenesis is the process by which male gametes - mature spermatozoa - are produced in the testis. This process requires exquisite control over many developmental transitions, including the self-renewal of the germline stem cell population, commitment to meiosis, and ultimately, spermiogenesis. While much is known about molecular mechanisms regulating single transitions at single time points in the mouse, much less is understood about how the spermatogenic progenitor cells, spermatogonia, or the meiotic cells, spermatocytes, of the testis change over developmental age.\n\nOur single-cell-mRNA-sequencing analysis is the first to profile both spermatogonia and spermatocytes from neonatal mice through adulthood, revealing novel gene expression dynamics and differential utilization of biological pathways. These discoveries help us to understand how the spermatogenic progenitors of this population modulate their activity to adapt to a changing testicular environment. Furthermore, they also begin to explain previously-observed differences - and deficiencies - in spermatocytes that are derived from the first \"wave\" of spermatogenesis. Overall, this dataset is the first of its kind to comprehensively profile gene expression dynamics in male germ cell populations over time, enriching our understanding of the complex and highly-orchestrated process of spermatogenesis.

genomics↗