Human PUM1 and PUM2 exhibit regulation of divergent mRNA targets in male germ cells

ABSTRACT Mammalian Pumilio (PUM) proteins are sequence-specific, RNA-binding proteins with wide-ranging roles, including germ cell development that has functional implications in fertility. Although human PUM1 and PUM2 are closely related to each other and recognize the same RNA binding motif, there is some evidence for functional diversity, particularly related to their roles in fertility. Here, by RNA sequencing (RNA-Seq) approaches, we identified separate mRNA pools regulated by PUM1 and PUM2 proteins in human male germ cells. Using global mass spectrometry-based profiling, we identified distinct PUM1- and PUM2-bound putative protein cofactors, most of them involved in RNA processing. Combinatorial analysis of RNA-Seq and mass spectrometry findings revealed that PUM1 and PUM2 may form distinct RNA-regulatory networks, with different roles in human reproduction and testicular tumorigenesis. Our findings highlight the functional divergence and versatility of PUM paralogue-based post-transcriptional regulation, offering insight into the mechanisms underlying their diverse biological roles and diseases resulting from their dysfunction.