Cloning and analysis of the HMG domains of ten Sox genes from Bombina maxima (Amphibia: Anura)

Abstract

Sox is a large gene family which encodes Sry-related transcription factors and contains a HMG box that is responsible for the sequence-specific DNA binding. In this paper, we obtained ten clones
representing HMG box-containing Sox genes (BmSox1a, BmSox1b, BmSox3a, BmSox3b, BmSox3c, BmSox11a, BmSox11b, BmSox11c, BmSox14, BmSox33) from male and female Bombina maxima
respectively and no sexual differences were observed, using highly degenerate primers designed from the conservative motif (HMG-box) of the human SRY gene. We want to reveal the gene duplication
process and gene trees for the Sox genes in this toad. The sequences analysis indicated that Sox1, Sox3 and Sox11 gene may be duplicated. The cloned Sox genes shared high sequence identity to the
homologous human SOX genes. Based on the amino acid sequence similarities, the phylogenetic analysis was carried out and the results suggested that nine of ten HMG domain-encoding sequences
are members of the SoxB and SoxC groups. BmSox33 and its homologous gene xSox33(Xenopus laevis) were found only in Discoglossidae and Xenopodidae in amphibian, but Sox33 has not been
found in other vertebrates up to now, and the origin of Sox33 gene is an interesting target in phylogenesis.