No abstract

Bone morphogenetic protein 4 (BMP4) is a member of the bone morphogenetic protein family (BMPs). It is involved in the development and cycle of hair follicle, as well as, is thought to be a potential candidate gene for cashmere traits in goats. In the present study, we isolated and characterized a full-length open reading frame (ORF) of BMP4 cDNA from the skin tissue of Liaoning cashmere goat, and investigated the transcriptional pattern and methylation status of BMP4 gene in skin tissue of this breed during different stages of hair follicle cycle. The sequence analysis indicated that the isolated cDNA was 1264-bp in length containing a complete ORF of 1230-bp. It encoded a precursor peptide of 409 amino acids with a signal peptide of 19 amino acids. The structural analysis indicated that goat BMP4 contains typical TGF-β propeptide and TGF-β domains. In skin tissue, BMP4 is generally transcribed in an ascendant pattern from anagen to telogen. The methylation level of 5' flanking regulatory region of BMP4 gene might be involved in its mRNA expression in skin tissue: a higher BMP4 methylation level in skin coincides with a lower expression of BMP4 mRNA. These results from the present work provided a foundation for further insight into the functional and regulatory characteristics of BMP4 in the development and cycle of hair follicle in Liaoning Cashmere goat.

Homeobox protein Hox-C8 (HOXC8) is a member of Hox family. It is expressed in the dermal papilla of the skin and is thought to be associated with the hair inductive capacity of dermal papilla cells. In the present study, we isolated and characterized a full-length open reading frame of HOXC8 cDNA from the skin tissue of Liaoning cashmere goat, as well as, established a phylogenetic relationship of goat HOXC8 with that of other species. Also, we investigated the effect of methylation status of HOXC8 exon 1 at anagen secondary hair follicle on the cashmere fiber traits in Liaoning cashmere goat. The sequence analysis indicated that the obtained cDNA was 1134-bp in length containing a complete ORF of 729-bp. It encoded a peptide of 242 amino acid residues in length. The structural analysis indicated that goat HOXC8 contained a typical homeobox domain. The phylogenetic analysis revealed that Capra hircus HOXC8 had a closer genetic relationship with that of Ovis aries, followed by Bos Taurus and Bubalus bubalis. The methylation analysis suggested that the methylation degree of HOXC8 exon 1 in anagen secondary hair follicle might be involved in regulating the growth of cashmere fiber in Liaoning cashmere goat. Our results provide new evidence for understanding the molecular structural and evolutionary characteristics of HOXC8 in Liaoning cashmere goat, as well as, for further insight into the role of methylation degree of HOXC8 exon 1 regulates the growth of cashmere fiber in goat.

Insulin-like growth factor I (IGF1) is a member of the insulin superfamily. It performs important roles in the proliferation and differentiation of skin cell and control of hair cycles and is thought to be a potential candidate gene for goat cashmere traits. In this work, we isolated and characterized three kinds of IGF1 mRNA splicing variants from the liver of Liaoning Cashmere goat, and the expression characterization of the IGF1 mRNA splicing variants were investigated in skin and other tissues of Liaoning cashmere goat. The sequencing results indicated that the classes 1w, 1, and 2 of IGF1 cDNAs in Liaoning cashmere goat, each included an open reading frame encoding the IGF1 precursor protein. The deduced amino acid sequences of the three IGF1 precursor proteins differed only in their NH2-terminal leader peptides. Through removal of the signal peptide and extension peptide, the three IGF1 mRNA splicing variants (classes 1w, 1, and 2) resulted in the same mature IGF1 protein in Liaoning cashmere goat. In skin tissue of Liaoning cashmere goat, class 1 and class 2 were detected in all stages of hair follicle cycling, and they had the highest transcription level at anagen, and then early anagen; whereas at telogen both classes 1 and 2 had the lowest expression in mRNA level, but the class 1 appears to be relatively more abundant than class 2 in skin tissue of Liaoning cashmere goat. However, the class 1w transcript was not detected in the skin tissues. Three classes of IGF1 mRNA were transcribed in a variety of tissues, including heart, brain, spleen, lung, kidney, liver, and skeletal muscle, but class 1 IGF1 mRNA was more abundant than classes 1w and 2 in the investigated tissues.