Molecular cloning and bioinformatics analysis of MT-IV in the yak

In this study,coding sequence of yak metallothionein(MT-IV) gene was cloned by reverse transcriptase-polymerase chain reaction(RT-PCR) using the gene specific primers YMT-IVSP1 and YMT-IVSP2,and then 2 pairs specific primers were designed for cloning 2 introns of the yak MT-IV by comparing with the human MT-IV gene.The sequence length of MT-IV gene in yak was 2 099 bp(GenBank Accession No.: EU665491),including 3 exons and 2 introns.The coding regions were composed by 189 nucleotides encoding a 62-amino acid protein which contained 20 cysteine residues and no aromatic AA.The length of 2 introns were 1 392 bp and 518 bp,respectively.The MT-IV proteins were highly conserved among yak,cattle,sheep,goat,dog,mouse,human and horse,which had a glutamate insertion at position 5 relative to the classical MT-I and MT-I1 proteins,and also had the conserved motifs of MTs,such as C-X-C,C-C-X-C-C,C-X-X-C.These results indicated that the yak MT-IV had same molecular characteristics with other mammalian species,but it was necessary to study the expression level of the yak MT-IV in stratified squamous epithe1iat.