Studies on expression of eIF2α kinases in the mouse male germ cells

Abstract

The mammalian male germ cells should be maintained below the core body temperature for their successful development. A previous study in my laboratory reported that eIF2α (α subunit of eukaryotic translation initiation factor 2) phosphorylation is one of immediate responses of male germ cells against heat stress. In this work, the expression of eIF2α protein was observed in all stages of male germ cells. However, phospho-eIF2α was detected only at cytoplasm of germ cell stages up to early pachytene spermatocytes by heat treatment. In order to identify a candidate kinase responsible for eIF2α phosphorylation upon heat stress in male germ cells, I examined expression of the four known eIF2α kinases (HRI, PKR, PERK, and GCN2) in mouse testis. The results showed that all four eIF2α kinases are expressed with distinct developmental stage-specific manners. Furthermore, a phosphorylated form of PERK is detected in the testis from heat-treated mouse. These results suggest that PERK is the candidate kinase that phosphorylates eIF2α by sensing heat stress in the mouse male germ cells.