Molecular characterization of caprine KRTAP13-3 in Liaoning cashmere goat in China

Keratin-associated proteins are a main structural component of hair and wool fibers and may have effects on their characteristics. There are four KAP13 gene members that have been reported in humans, and the KAP13-3 gene has been identified in sheep and cattle, but it has not yet been identified in goats. This led us to search for the caprine KAP13-3 gene. In this study, the caprine KAP13-3 gene was polymerase chain reaction (PCR) amplified, and PCR single-stranded conformational polymorphism (PCR-SSCP) analysis was used to detect genetic variation in 214 Liaoning cashmere goats from China. PCR amplicons of 559 bp were obtained. Sequencing of the amplicons confirmed eight different sequences, and they were named alleles A – H . All of these sequences showed a high sequence homology to known KRTAP13-3 sequences from sheep and cattle. Nine nucleotide substitutions were identified within the KRTAP13-3 coding region, and all of these were nonsynonymous. All sequences showed an open reading frame of 471 nucleotides encoding 156 amino acids. This polypeptide contained high levels of serine (23.08–23.72 mol%), cysteine (10.26–11.54 mol%), and threonine (5.66 mol%). The polypeptide had high calculated pI values (9.02–9.59). The variation reported in the caprine KAP13-3 gene might affect gene expression, primary protein structure, and the character of the resultant cashmere fibers.