BRUNOL(Bruno-like protein), also named CELF(CUG-BP and ETR3 like factor), is a typical RNA binding protein with two consecutive RNA recognition motifs(RRM) in the N terminal and one in the C terminal. It has many functions in the post-transcriptional regulation of gene expression, such as alternative splicing, translation, degradation and editing. Until now, 6 members of Brunol family have been found in human, namely, Brunol 1-6 and 5 in Xenopus laevis:Brunol1-5 . Recently, we cloned all the 5 members of Brunol family in Xenopus laevis and found that Brunol1 is robustly and specifically expressed in the neural tube. To study the role of Brunol1 in neural development, we did loss-of-function and overexpression experiments in Xenopus embryos. Blocking of Brunol1 by specific morpholino leads to severe embryonic defects with curved bodies and defected eyes. These phenotypes can be rescued by co-injected Brunol1 mRNA. Interestingly, overexpression of Brunol1 can give rise to abnormal embryos with curved bodies. When injected in the head region, the head development was severely blocked. Through in situ hybridization, we checked the expression of several neural specific markers in Brunol1 injected embryos. We found that overexpression of Brunol1 clearly inhibited the expression of Krox-20, N-tubulin, Lhx2, Pax6, but not that of Sox2 and Otx2, suggesting a specific role of Brunol1 in neural differentiation. These results are instructive for elucidating Brunol1’s role in neurogenesis in vertebrate. Actins are a small family of ubiquitous proteins that are essential cytoskeletal components and are highly conserved during evolution. Actins are usually divided into two classes, the cytoplasmic and muscle actins, which have different functional roles. Here we systematically analyzed the actin genes in the genome of the primitive chordate amphioxus (Branchiostoma floridae). We found that amphioxus contains more that 30 actin genes, many of which are linked. Phylogenetic analysis suggest the amphioxus actin genes have clearly undergone expansion through tandem and clusteral duplications. The actin genes’ structure also varies a lot, containing 2 to 7 exons. We also cloned two muscle types of actin genes from the amphioxus and compared their expression patterns during early development. The slight difference in their expression suggests functional diversification of these actin genes. Our results shed light on the evolution both of actin genes themselves and of their functional roles in chordate development.
修改评论