The BRCA1/BARD1 complex recognizes pre-ribosomal RNA to facilitate homologous recombination

G6PC3 is involved in spermatogenesis by maintaining meiotic sex chromosome inactivation

Meiosis, a process unique to germ cells, involves formation and repair of double-stranded nicks in DNA, pairing and segregation of homologous chromosomes, which ultimately achieves recombination of homologous chromosomes. Genetic abnormalities resulted from defects in meiosis are leading causes of infertility in humans. Meiotic sex chromosome inactivation (MSCI) plays a crucial role in the development of male germ cells in mammals, yet its underlying mechanisms remain poorly understood. In this study, we illustrate the predominant presence of a protein known as glucose 6 phosphatase catalyzed 3 (G6PC3) in pachytene spermatocytes, with a high concentration in the sex body (XY body), suggesting its significant involvement in male germ cell development. By employing CRISPR-Cas9 technology, we generate mice deficient in the G6pc3 gene, resulting in complete meiotic arrest at the pachytene stage in spermatocytes and are completely sterile. Additionally, we observe abnormal XY body formation and impaired MSCI in G6pc3-knockout spermatocytes. These findings underscore G6pc3 as a new essential regulator that is essential for meiotic progression. G6PC3 is involved in spermatocyte during male spermatogenesis development by the maintenance of meiosis chromosome silencing.

The role of rRNA in maintaining genome stability

Over the past few decades, unbiased approaches such as genetic screening and protein affinity purification have unveiled numerous proteins involved in DNA double-strand break (DSB) repair and maintaining genome stability. However, despite our knowledge of these protein factors, the underlying molecular mechanisms governing key cellular events during DSB repair remain elusive. Recent evidence has shed light on the role of non-protein factors, such as RNA, in several pivotal steps of DSB repair. In this review, we provide a comprehensive summary of these recent findings, highlighting the significance of ribosomal RNA (rRNA) as a critical mediator of DNA damage response, meiosis, and mitosis. Moreover, we discuss potential mechanisms through which rRNA may influence genome integrity.

Transcription factors and miRNA act as contrary regulators of gene expression in the testis and epididymis of Bos indicus animals

Spermatogenesis is highly conserved among mammalians, but its gene expression and regulatory profile are not entirely known. As transcription factors (TFs) and miRNAs are crucial for gene expression regulation, identifying genes negatively regulated by miRNAs and positively regulated by TFs in the testis and epididymis can provide a deeper understanding of gene expression and regulatory patterns. To do this, we used expression data coming from RNA-Seq and miRNA-Seq experiments made with biopsies from testicular parenchyma, head of the epididymis, and tail of the epididymis of four Brahman bulls. We identified miRNA differentially expressed (DE) by comparing the three distinct tissues. A co-expression analysis combined with a regulatory impact factor approach identified miRNAs and TFs with regulatory impact over gene expression regulation in the Bos indicus tissues studied. We identified 116 DE miRNAs, 206 miRNAs and 237 TFs with a significant regulatory impact on mRNA patterns in the tissues' comparisons. bta-miR-196b was the only DE miRNA for all tissue comparisons and it may be a regulator of spermatogenesis through its links with adipogenesis and insulin biosynthesis. DE genes and TFs involved in contrary regulations between the epididymis head and testis parenchyma were associated with spermatogenesis, sexual reproduction, and sperm motility. Our results provide possible mechanisms, governed by the contrary effect of miRNA and TF, leading to the differential expression between the studied tissues. We have demonstrated that our predictions of miRNAs and TFs co-regulations over target DE genes can retrieve known regulatory mechanisms and predict new ones that merit further validation.