Let-7b promotes alpaca hair growth via transcriptional repression of TGFβR I

The young male alpaca ear and the back skins were used to investigate the effect of transforming growth factor receptor-beta I (TGF beta R I) on alpaca hair follicles and hair growth. The expression level and location of TGF beta R I in alpaca ear and dorsal skin were detected through real-time quantitative PCR (RT-PCR) and paraffin section immunohistochemical technique (ICC-P). The results shown TGF beta R I was lower expression in back skin compared to ear skin and the mean density of the positive reaction in ear skin was significantly higher than back skin. The targeted relationship with let-7b was detected using the dual-luciferase reporter vector of TGF beta R I, which showed a significant target relationship between let-7b and TGF beta R I. After transfection with let-7b eukaryotic expression vector, the relative mRNA expression of TGF beta R I in alpaca skin fibroblasts did not differ, while the relative protein level was significantly decreased. In summary, a higher TGF beta R I expression level in the ear skin suggests that TGF beta R I may inhibit coat hair elongation. Further studies showed TGF beta R I protein was downregulated by let-7b through transcriptional repression. (c) 2015 Elsevier B.V. All rights reserved.