Biological Function of Keratin-Associated Protein 26.1 of Liaoning Cashmere Goat Gene Family

We obtained the full-length cDNA clone of KAP26.1 in Liaoning cashmere goat, and then we further investigated biological functions of KAP26.1. First, we discovered KAP26.1 was specifically expressed in internal root sheath of skin hair follicles by semi-quantitative reverse transcription and polymerase chain reaction (semi-quantitative RT-PCR), hybridization in situ; immunohistochemistry revealed KAP26.1 was located in the internal and external root sheaths. Next, quantitative real-time polymerase chain reaction (qRT-PCR) results showed relative KAP26.1 expression quantity was significantly different between primary and secondary follicles during anagen, catagen, and remarkably increased during telogen. Moreover, after inhibiting Noggin expression, we found relative KAP26.1 expression quantity significantly declined; after KAP26.1 overexpression, we found relative Noggin expression quantity highly significantly declined. Finally, we found MT played a positive role in KAP26.1 and KAP26.1 expression; FGF5 and IGF-1 palyed a negative role in KAP26.1 and blocked the degradation of KAP26.1. The results revealed KAP26.1 played an important role in regulating fine hair development.