Biology subjects

Previato, L.

Publications and source records attributed to Previato, L..

5 recordsLinked to original sources

bioRxiv2025

A novel CHD4-CTCF regulatory axis drives key developmental programs and transitions in male germ cells.

Sustained gamete production and testis development relies in developmental programs and transitions such as spermatogonia differentiation, meiosis, and spermiogenesis. Chromatin remodeling complexes and CTCF are key regulators of these processes by controlling specific patterns of gene expression across gamete development. Although the CHD4 chromatin remodeler and CTCF have been implicated in spermatogonia development, a mechanism explaining their cooperation is missing. We also do not know CHD4 and CTCF role in later stages of spermatogenesis. Our studies reveal that germ cell-specific deletion of CHD4 results in spermatogonia development defects and affects meiotic-specific functions such as homologous chromosome synapsis. Combined analysis of genome-wide chromatin binding and single cell gene transcription showed that CHD4 controls specific gene expression programs important for spermatogonia differentiation, transition into meiosis, and meiotic specific processes. Mechanistically, this can be explained by a pervasive role for CHD4 in controlling CTCF chromatin binding and transcriptional function. The discovery of a functional interplay between CHD4 and CTCF reveals a novel axis of gene expression control, integrating chromatin structure and transcriptional outcomes. This interaction is essential in orchestrating early testis development and meiotic processes, ensuring that the correct number of chromosomes is faithfully transmitted to the next generation.

developmental biology↗

bioRxiv2025

Kinesin drive meiotic chromosome dynamics via interaction with the KASH5-LINC complex

Telomere-led rapid prophase chromosome movements (RPMs) during meiotic prophase are critical for homologous chromosome pairing and proper meiotic progression. These movements are generated by the cytoskeleton and are transmitted to the telomeres via the LINC complex, yet the cytoplasmic components that generate these forces remain poorly defined. Among candidates of microtubule-associated motor proteins in mouse primary spermatocytes, we confirmed KIF5B as a specific interactor of the KASH5-LINC complex. Total internal reflection fluorescence microscopy and microtubule sedimentation assays performed with purified recombinant proteins suggest a direct interaction between KASH5 and KIF5B on microtubules, enhanced by MAP7, a known KIF5B-recruiting and activating cofactor. Mapping the KIF5B-binding surface of KASH5 revealed that KASH5 N-terminal EF-hand domains mediate the interaction. Further, in vivo KIF5B-KASH5 interaction and KIF5B role in RPMs are evidenced as (1) KIF5B is recruited by KASH5-SUN1 to the nuclear envelope in two different cultured somatic cell models, (2) KIF5B is telomere-associated and colocalizes with KASH5, and microtubules associated with the nuclear envelope in mouse spermatocytes, and (3) chemical inhibition of KIF5B reduces telomere-led chromosome motions. Altogether, our findings identify the KIF5B kinesin as a previously unrecognized component of the force-generating machinery that drives chromosome movement during meiotic prophase I, acting through KASH5 as a specific nuclear membrane adaptor.

cell biology↗

bioRxiv2019

CHD4-NURD controls spermatogonia survival and differentiation

Testis development and sustained germ cell production in adults rely on the establishment and maintenance of spermatogonia stem cells and their proper differentiation into spermatocytes. Chromatin remodeling complexes regulate critical processes during gamete development by restricting or promoting accessibility of DNA repair and gene expression machineries to the chromatin. Here, we investigated the role of CHD4 and CHD3 catalytic subunits of the NURD complex during spermatogenesis. Germ cell-specific deletion of Chd4 early in gametogenesis, but not Chd3, resulted in arrested early gamete development due to failed cell survival of neonate undifferentiated spermatogonia stem cell population. Candidate assessment revealed that CHD4 controls expression of Dmrt1 and its downstream target Plzf, both described as prominent regulators of spermatogonia stem cell maintenance. Our results show the requirement of CHD4 in mammalian gametogenesis pointing to functions in gene expression early in the process.

developmental biology↗

bioRxiv2019

PSMC3 is required for spermatogonia niche establishment in mouse spermatogenesis

Males produce millions of spermatozoa each day, which are originated from spermatogonia. Spermatogonia niche establishment and maintenance and the subsequent haploidization of spermatocytes in meiosis are hallmarks of this process. The function of the individual players and coordinated mechanisms regulating different stages of gametogenesis in mammals are not well understood. In this work we focused on the role of PSMC3 in mouse gametogenesis. We observed that Psmc3 is highly expressed in mouse testis, and it is widely expressed in different stages of gamete formation. Conditional deletion of Psmc3 results in both male and female impairment of gonad development at early pre-meiotic stages, but has no apparent effect on meiosis progression. This is likely a consequence of abnormal spermatogonia niche establishment and/or maintenance, revealed by a massive loss of undifferentiated spermatogonia. Our work defines a fundamental role of PSMC3 functions in spermatogenesis during spermatogonia development with direct implications in fertility.

developmental biology↗

bioRxiv2018

Shugoshin protects centromere pairing and promotes segregation of non-exchange partner chromosomes in meiosis

Faithful chromosome segregation during meiosis I depends upon the formation of connections between homologous chromosomes. Crossovers between homologs connect the partners allowing them to attach to the meiotic spindle as a unit, such that they migrate away from one another at anaphase I. Homologous partners also become connected by pairing of their centromeres in meiotic prophase. This centromere pairing can promote proper segregation at anaphase I of partners that have failed to become joined by a crossover. Centromere pairing is mediated by synaptonemal complex (SC) proteins that persist at the centromere when the SC disassembles. Here, using mouse spermatocyte and yeast model systems, we tested the role of shugoshin in promoting meiotic centromere pairing by protecting centromeric synaptonemal components from disassembly. The results show that shugoshin protects centromeric SC in meiotic prophase and, in anaphase, promotes the proper segregation of partner chromosomes that are not linked by a crossover. SIGNIFICANCEMeiotic crossovers form a connection between homologous chromosomes that allows them to attach to the spindle as a single unit in meiosis I. In humans, failures in this process are a leading cause of aneuploidy. A recently described process, called centromere pairing, can also help connect meiotic chromosome partners in meiosis. Homologous chromosomes become tightly joined by a structure called the synaptonemal complex (SC) in meiotic prophase. After the SC disassembles, persisting SC proteins at the centromeres mediate their pairing. Here, studies in mouse spermatocytes and yeast are used to show that the shugoshin protein helps SC components persist at centromeres and helps centromere pairing promote the proper segregation of yeast chromosomes that fail to become tethered by crossovers.

cell biology↗