The Identification of Two CYP17 Alleles in the South African Angora Goat

Abstract

South African Angora goats (Capra hircus) are susceptible to cold stress, due to the inability of the adrenal cortex to produce sufficient levels of cortisol. Two CYP17 isoforms were identified, cloned and characterized in this study. Sequence analysis revealed three amino acid differences between the two CYP17 isoforms, which resulted in a significant difference in 17,20 lyase activity of the expressed enzymes in both the presence and absence of cytochrome b5. Furthermore, cotransfections with 3βHSD revealed that one CYP17 isoform strongly favours the Δ5 steroid pathway. Our data implicates CYP17 as the primary cause of the observed hypoadrenocorticoidism in the South African Angora goat.