A Novel Mechanism for Transcription Termination in the mod(mdg4) Locus of Drosophila melanogaster

This study investigated an alternative mechanism of transcription termination that occurs independently of polyadenylation. We focused on a non-canonical transcription terminator (NTT) identified in the <i>mod(mdg4)</i> gene of <i>Drosophila melanogaster</i>. Using a developed model system, we demonstrated that the minimal functional unit of the NTT consists of 79 nucleotides that form a specific secondary RNA structure. Our results indicate that transcripts generated from the NTT exhibit reduced stability and are hindered in their export to the cytoplasm. An NTT from the distantly related species <i>D. willistoni</i> could function as a transcription terminator in <i>D. melanogaster</i> cells, highlighting the importance of conserved motifs for NTT functionality. At the same time, the NTT did not function in human cells, suggesting that the interaction of the NTT with specific protein factors is required to terminate transcription.