A male-specific doublesex isoform reveals an evolutionary pathway of sexual development via distinct alternative splicing mechanisms

Sex-specific mRNA alternative splicing patterns and Dmrt1 isoforms contribute to sex determination and differentiation of oyster

Alternative splicing (AS) of pre-mRNA is a crucial mechanism that regulates the expression of genes involved in sex determination and differentiation. Despite its importance, AS has been rarely characterized in molluscs. In this study, PacBio Iso-Seq was employed to obtain full-length transcriptome and unveil AS patterns of gonads in the Pacific oyster Crassostrea gigas. A total of 24,783 AS events were identified across 6259 genes, with many enriched in phosphorylation-related processes. Splicing factors were found to drive a high frequency of AS events in gonads. Significant sex-based differences in isoform abundance and the incidence of AS events were observed. Comparative analysis of mature female and male gonads revealed a subset of overlapping differential alternative splicing genes and differentially expressed genes enriched in processes related to microtubule function and cell motility. In addition, the expression levels of sex-biased genes were found correlated with their isoform number in both female and male gonads. A novel isoform of Dmrt1 was identified with male specific expression in mature gonads. This study provides the first comprehensive understanding of full-length transcriptome and AS patterns in molluscan gonads, shedding light on the post-transcriptional regulatory mechanisms underlying sex determination and differentiation in molluscs and potentially across other animals.

Therapeutic potential of natural antisense transcripts and various mechanisms involved for clinical applications and disease prevention

Antisense transcription, a prevalent occurrence in mammalian genomes, gives rise to natural antisense transcripts (NATs) as RNA molecules. These NATs serve as agents of diverse transcriptional and post-transcriptional regulatory mechanisms, playing crucial roles in various biological processes vital for cell function and immune response. However, when their normal functions are disrupted, they can contribute to human diseases. This comprehensive review aims to establish the molecular foundation linking NATs to the development of disorders like cancer, neurodegenerative conditions, and cardiovascular ailments. Additionally, we evaluate the potential of oligonucleotide-based therapies targeting NATs, presenting both their advantages and limitations, while also highlighting the latest advancements in this promising realm of clinical investigation.Abbreviations: NATs- Natural antisense transcripts, PRC1- Polycomb Repressive Complex 1, PRC2- Polycomb Repressive Complex 2, ADARs- Adenosine deaminases acting on RNA, BDNF-AS- Brain-derived neurotrophic factor antisense transcript, ASOs- Antisense oligonucleotides, SINEUPs- Inverted SINEB2 sequence-mediated upregulating molecules, PTBP1- Polypyrimidine tract binding protein-1, HNRNPK- heterogeneous nuclear ribonucleoprotein K, MAPT-AS1- microtubule-associated protein tau antisense 1, KCNQ1OT- (KCNQ1 opposite strand/antisense transcript 1, ERK- extracellular signal-regulated kinase 1, USP14- ubiquitin-specific protease 14, EGF- Epidermal growth factor, LSD1- Lysine Specific Demethylase 1, ANRIL- Antisense Noncoding RNA in the INK4 Locus, BWS- Beckwith-Wiedemann syndrome, VEGFA- Vascular Endothelial Growth component A.