The role of heat shock proteins in rapid cold hardening in the flesh fly Sarcophaga crassipalpis

Rapid cold hardening (RCH) is the protection granted to an organism when a cold shock is preceded by exposure to a moderately low temperature. To better understand the possible role that Heat shock proteins (Hsps) play in RCH and cold recovery transcription levels were assessed for seven different Hsps. In this study red eye pharate adults of the flesh fly Sarcophaga crassipalpis were exposed to a -10ºC cold shock and then allowed to recover both with and without a RCH treatment (2h at 0 ºC). Samples were generated during RCH and recovery and assessed using quantitative Polymerase chain reaction. Hsp23, Hsp27, Hsp40, Hsp70, and Hsp90 were significantly upregulated during recovery with and with out pretreatment when compared with untreated controls. Hsp90 was upregulated during RCH. Although Hsp25 and Hsp27 did not respond during RCH, levels of expression during recovery were affected by RCH. Hsp60 changed little in response to any of the above treatments. These data demonstrate a robust Hsp response during recovery from cold and suggest an important role for Hsps in cold recovery. These data also suggest a possible role for Hsp90, Hsp25, and Hsp27 in rapid cold hardening, thus allowing us to begin dissecting specific roles for different Hsps in cold response.