A polycistronic locus encodes both a tumor-suppressive microRNA and a long non-coding RNA regulating testis morphology in Drosophila.

The impact of non-coding RNAs on stem cell biology and differentiation processes is an important and incompletely understood area of research. Using the testes of as a valuable system for investigating these processes, we identified a polycistronic locus from which two non-coding transcripts, and the long non-coding RNA (lncRNA) , are produced, with alternative polyadenylation implicated in regulation of their differential expression levels. We report here that each transcript has a distinct role in Drosophila testes; the increased expression of results in the disruption of the muscle sheath covering the testis, and the absence of leads to the emergence of germ-cell tumors in developing flies. The deficiency of increases Notch signaling activity in somatic cyst cells, upregulates multiple predicted targets of , and drives germline tumorigenesis. This work implicates as a tumor suppressor that modulates Notch signaling strength and suggests alternative polyadenylation as a novel mechanism for regulation of miRNA expression.