Uncovering the long non-coding RNAs in Drosophila: Tissue specific expressions and functional roles in reproductive development.

Long non-coding RNAs (lncRNAs) have emerged as key regulators of gene expression, with a significant role in development and tissue-specific expression. In Drosophila melanogaster, testis demonstrates the highest repertoire of lncRNAs among male tissues while, ovaries exhibit a substantial distribution of lncRNAs in females. This tissue- and sex-specific distribution highlights the multifaceted roles of lncRNAs in reproductive and neural contexts. Several testis-enriched lncRNAs are vital in spermatogenesis, and their disruption leads to abnormal germline stem cell proliferation, spermatogonia tumour-like phenotypes, and infertility. These effects are frequently manifested through competitive endogenous RNA (ceRNA) networks, in which lncRNA precisely regulates the activity of microRNAs (miRNAs) and protein-coding genes. The genetic flexibility of the Drosophila system, particularly through the GAL4/UAS system and CRISPR-based editing, offers numerous opportunities to analyse lncRNA function in vivo. Bioinformatics approaches further enhance these tools by facilitating the novel lncRNA discoveries, functional motif predictions, and cross-species comparisons that reveal evolutionary conservation with humans, mice, zebrafish, and other Drosophila groups. Despite growing interest, the functional landscape of lncRNAs in Drosophila remains an emerging and still poorly characterized field, particularly in terms of mechanistic understanding and cross-tissue regulatory networks. This review coalesces current knowledge on the abundance, mutational effects, and functional insights of lncRNAs in Drosophila testis and brain, highlighting their value as a model for deciphering conserved lncRNA biology and its implications for human reproductive health.