Expression profiling of major heat shock protein genes during different seasons in cattle (Bos indicus) and buffalo (Bubalus bubalis) under tropical climatic condition.

Heat shock proteins consist of highly conserved stress proteins, expressed in response to stress and play crucial roles in environmental stress tolerance and adaptation. The present study was conducted to identify major types of genes under the HSP70 family and other HSPs and to evaluate their expression pattern in Sahiwal and Tharparkar breeds of zebu cattle (Bos indicus) and Murrah buffalo (Bubalus bubalis) with respect to different seasons. Quantitative real time polymerase chain reaction was performed to analyze the transcript variants of three HSP70 family genes (HSPA1A, HSPA1B, and HSPA8) and HSP10, HSP60, HSP90 and HSF1 in each breed. The major finding of this study was the higher abundance of all the studied HSP genes during summer and winter compared to spring season, but the magnitude of increase was higher during summer as compared to winter. HSPA1A and HSPA1B genes showed maximal induction (P<0.001) during summer and winter while HSP60 and HSP10 were found to be the second most abundantly expressed HSPs. The relative mRNA abundance of HSF1 significantly increased (P<0.001) in Murrah buffalo compared to Tharparkar and Sahiwal cattle during summer and winter. Expression pattern of heat shock protein genes indicated that amongst the breeds, the expression was higher in Murrah buffalo compared to Sahiwal and Tharparkar cattle, thereby indicating the more adaptive capacity of later during periods of stress. Hence, this study suggests that heat shock protein genes may be conveniently used as biomarkers for assessing stress response in cattle and buffalo and the expression is species and breed-specific. Furthermore, the variation in expression is associated with heat tolerance and adaptation to different climatic conditions.