A hsp70-related gene is constitutively highly expressed in testis of rat and mouse.

The expression pattern of major heat shock related genes (hsp70 gene family) in various organs of mouse and rat was investigated using Northern blot analysis. Heat shock gene related transcripts were detected in total RNA by hybridization with cloned mouse hsp70 gene sequences. Cells of various organs of intact mouse and rat constitutively synthesize a 2.2 kb and a 2.5 kb RNA. Exceptionally high levels of the 2.5 kb RNA, 50-250 fold higher than in other tissues are found in testis of both rodents. The 2.5 kb RNA hybridizes strongly to an extended region of mouse hsp70 gene; it also hybridizes poorly to the Drosophila hsp70 gene. The data suggest that the 2.5 kb RNA is transcribed from a hsp70-related gene in mouse and rat.