Phylogenetic analysis and developmental expression of brp-like genes in amphioxus and zebrafish.

The brp-like genes in amphioxus (Branchiostoma belcheri tsingtauense) and in zebrafish (Danio rerio) are reported. The putative brp-like proteins are orthologous to the ancestor of the human brain protein 239FB and 239AB. Previous studies showed that human brain protein 239 might play a role in central nervous system development and function. In this study, the transcripts of zebrafish brp-like gene are mainly located in the developing central neural system in embryo and larva similar to its orthologous genes in human. In contrast, the developmental expression pattern of amphioxus brp-like gene suggests that the gene might be involved in the development of the notochord, pharynx, gills and gut in amphioxus embryos and larvae. Phylogenetic analysis shows that the amphioxus brp-like gene is closer to the orthologous genes in vertebrates than those in invertebrates. The results suggest that the function of the brain protein 239 family genes may change in evolution.