HSPA2 is a member of the HSP70 family of heat-shock proteins that serve as molecular chaperones. Hspa2-cre expression mimics the spermatogenic cell-specific expression of endogenous HSPA2 within the testis, being first observed in leptotene/zygotene spermatocytes. Expression of the transgene is also detected at restricted sites in the brain, as occurs for endogenous HSPA2.

Researchers at NIEHS developed the first transgenic mouse line that expresses Cre-recombinase under the control of the promoter of the heat shock protein A2 (Hspa2) gene. Expression of the Hspa2-Cre transgene during meiosis in male germ cells makes these mice a useful tool for defining the roles of genes expressed at different times during spermatogenesis or expressed in spermatogenic cells.