Breeding and Genetics: Dairy Cattle

Protein-damaging stresses, including heat shock, cold, altered pH and oxygen deprivation induce the expression of a subgroup of molecular chaperones, called heat shock proteins (Hsp), which consist of several protein families designated by their molecular weight, such as the Hsp90, Hsp70, Hsp60, and the small Hsp (sHsp) families. Small heat shock proteins (sHsp) with a molecular mass of 15–30 kDa are ubiquitous and conserved. This large family of proteins is present within the prokaryotic and eukaryotic cell as large oligomeric complexes, ranging in size from 200 to 800 kDa. Unlike the high molecular weight Hsp, which are involved in protein folding in vivo, under normal conditions, sHsp play an important role in protecting organism from stress. The sHsp share an evolutionarily conserved sequence of 80–100 amino acids, located in the C-terminal region, and called “alpha-crystallin domain.” Ten active genes for sHsp have been identified in the human genome. This project focused on 10 α-crystallin related Hsps belonging to the sHsp molecular chaperone family: HspB1HspB10. It is anticipated that the recently completed annotated sequence of the cattle genome will lead to identification of genes for disease resistance and higher quality meat. The purpose of this project was to determine if genes coding for human sHsp are found in the bovine genome, and if so, how highly the sequences were conserved across the 2 species. The NCBI search engine, BLAST, and CLUSTALW on Biology Workbench were used. Homologs of 10 α-crystallin human small heat shock protein (sHsp) molecular chaperone family (HspB1HspB10) were found within the bovine genome and single nucleotide differences identified in silico. The sequence for human sHspB9 expressed exclusively in the testis and cancerous tissue did not identify related sequences in the bovine.