The leucine-rich repeats and PDZ (LAP) family of genes are crucial for the maintenance of cell polarity as well as for epithelial homeostasis and tumor suppression in both vertebrates and invertebrates.Four members of this gene family are known:densin,erbin,scribble and lano.Here,we identified the four members of the LAP gene family in Xenopus tropicalis and studied their expression patterns during embryonic development.The Xenopus LAP proteins show a conserved domain structure that is similar to their homologs in other vertebrates.In Xenopus embryos,these genes were detected in animal cap cells at the early gastrula stage.At later stages of development,they were widely expressed in epithelial tissues that are highly polar in nature,including the neural epithelia,optic and otic vesicles,and in the pronephros.These data suggest that the roles of the Xenopus LAP genes in the control of cell polarity and morphogenesis are conserved during early development.Erbin and lano show similar expression patterns in the developing head,suggesting potential functional interactions between the two molecules in vivo.
YANG QiuTanLV XiaoYanKONG QingHuaLI ChaoCuiZHOU QinMAO BingYu
The evolution of the central nervous system（CNS） is one of the most striking changes during the transition from invertebrates to vertebrates. As a major source of genetic novelties,gene duplication might play an important role in the functional innovation of vertebrate CNS.In this study,we focused on a group of CNS-biased genes that duplicated during early vertebrate evolution.We investigated the tempo-spatial expression patterns of 33 duplicate gene families and their orthologs during the embryonic development of the vertebrate Xenopus laevis and the cephalochordate Brachiostoma belcheri.Almost all the identified duplicate genes are differentially expressed in the CNS in Xenopus embryos,and more than 50%and 30%duplicate genes are expressed in the telencephalon and mid-hindbrain boundary,respectively,which are mostly considered as two innovations in the vertebrate CNS.Interestingly,more than 50%of the amphioxus orthologs do not show apparent expression in the CNS in amphioxus embryos as detected by in situ hybridization,indicating that some of the vertebrate CNS-biased duplicate genes might arise from non-CNS genes in invertebrates.Our data accentuate the functional contribution of gene duplication in the CNS evolution of vertebrate and uncover an invertebrate non-CNS history for some vertebrate CNS-biased duplicate genes.
Yuan ChenYun DingZumingZhangWen WangJun-Yuan ChenNaoto UenoBingyu Mao
