Wake-up-call, a lin-52 paralogue, and Always early, a lin-9 homologue physically interact, but have opposing functions in regulating testis-specific gene expression

► wake-up-call (wuc), a paralogue of lin-52 functions in the Drosophila male germline. ► Wuc protein physically interacts with the lin-9 homologue, Aly. ► wuc is essential for male fertility. ► wuc loss of function causes defects in gene expression in testes. ► Transcription of aly target genes in testes can be rescued by wuc loss of function.