Variation in the Caprine Keratin-Associated Protein 27-1 Gene is Associated with Cashmere Fiber Diameter.

Mengli Zhao,Liyan Hu,Yize Song,Shaobin Li,Yuzhu Luo,Xiayang Jin,Xiu Liu,Jiqing Wang,Huitong Zhou,Jon G H Hickford,Zhiyun Hao,Jiang Hu,Xinmiao Wu

doi:10.3390/genes11080934

Abstract

Variation in some caprine keratin-associated protein (KAP) genes has been associated with cashmere fiber traits, but many KAP genes remain unidentified in goats. In this study, we confirm the identification of a KAP27-1 gene (KRTAP27-1) and describe its effect on cashmere traits in 248 Longdong cashmere goats. A polymerase chain reaction–single strand conformation polymorphism (PCR-SSCP) analysis was used to screen for sequence variation in this gene, and three sequence variants (named A to C) were found. These sequences have the highest similarity (77% identity) to a human KRTAP27-1 sequence, while sharing some homology with a predicted caprine KRTAP27-1 sequence ENSCHIG00000023347 in the goat genome construct (ARS1:CM004562.1) at chromosome 1 position 3,966,193–3,973,677 in the forward strand. There were two single nucleotide polymorphisms (SNPs) detected in the coding sequence, including one nonsynonymous SNP (c.413C/T; p.Ala138Val) and one synonymous SNP (c.495C/T). The C variant differed from A and B at c.413C/T, having cytosine in its nucleotide sequence, while the B variant differed from A and C at c.495C/T, having thymine in its nucleotide sequence. Goats of the genotypes AB and BB produced cashmere fibers of higher mean fiber diameter (MFD) than goats of genotype AA, but no difference in MFD was detected between the AB and BB goats. These results suggest that B is associated with increased MFD. Expression of the caprine KRTAP27-1 sequence was predominantly detected in the skin tissue of goats but not or only weakly detected in other tissues, including longissimus dorsi muscle, heart, kidney, liver, lung and spleen.

Highlights

Cashmere fiber is produced by secondary hair follicles
We report the identification of intronless KRTAP27-1 sequences amplified directly from goat DNA and describe variation in these sequences and the locations of expression of this gene; we describe the association of this gene with cashmere fiber traits in Longdong cashmere goats
Eleven previously described caprine keratin-associated protein (KAP) genes were found in this region, including caprine KRTAP11-1, KRTAP7-1, KRTAP8-1, KRTAP8-2, KRTAP20-2, KRTAP20-1, KRTAP15-1, KRTAP13-1, KRTAP13-3, KRTAP28-1 and KRTAP24-1 (Figure 1)

Summary

Introduction

Cashmere fiber is produced by secondary hair follicles. The fiber has the characteristics of being light, soft, strong, elastic and a good thermal insulator, and it is referred to as ‘soft gold’, as it plays an important role in the textile industries [1]. The price paid for cashmere fibers is typically. Curly fiber length and mean fiber diameter (MFD) are the most important traits in determining quality. The KAPs form a matrix and cross-link with cysteine residues on the keratins and other KAPs, through the formation of disulfide bonds. They typically possess a high content of either cysteine or glycine and tyrosine, and they have historically been classified into three broad groups based on their amino acid composition: the high sulfur (HS) group with less than 30 mol% cysteine, the ultrahigh sulfur (UHS) group with more than 30 mol% cysteine and the high glycine/tyrosine (HGT) group containing

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Conclusion