The Wnt/β-catenin signaling pathway plays a crucial role in the embryonic development of metazoans. Although the pathway has been studied extensively in many model animals, its function in amphioxus, the most primiti...The Wnt/β-catenin signaling pathway plays a crucial role in the embryonic development of metazoans. Although the pathway has been studied extensively in many model animals, its function in amphioxus, the most primitive chordate, remains largely uncharacterized. To obtain basic data for functional analysis, we identified and isolated seven genes （Lrp5/6, Dvl, APC, Ckla, CklS, Gsk3β, and Gro） of the Wnt/β-catenin signaling pathway from the amphioxus （Branchiostoma floridae） genome. Phylogenetic analysis revealed that amphioxus had fewer members of each gene family than that found in vertebrates. Whole-mount in situ hybridization showed that the genes were maternally expressed and broadly distributed throughout the whole embryo at the cleavage and blastula stages. Among them, Dvl was expressed asymmetrically towards the animal pole, while the others were evenly distributed in all blastomeres. At the mid-gastrula stage, the genes were specifically expressed in the primitive endomesoderm, but displayed different patterns. When the embryo developed into the neurula stage, the gene expressions were mainly detected in either paraxial somites or the tail bud. With the development of the embryo, the expression levels further decreased gradually and remained only in some pharyngeal regions or the tail bud at the larva stage. Our results suggest that the Wnt/β-catenin pathway might be involved in amphioxus somite formation and posterior growth, but not in endomesoderm specification.展开更多
Amphioxus, also called lancelet or cephalochordate, is a promising model organism owning to its particularly evolu- tionary position, simple genome content and comparable body plan to that of vertebrates （Holland et ...Amphioxus, also called lancelet or cephalochordate, is a promising model organism owning to its particularly evolu- tionary position, simple genome content and comparable body plan to that of vertebrates （Holland et aL, 2004; Bertrand and Escriva, 2011）. However, use of amphioxus as a model or- ganism has been limited for many years because of lack of an efficient genomic modification method. Recently, several revolutionary gene targeting methods that could induce directed mutations, insertions and deletions at intended target sites, have been developed （Gaj et al., 2013）.展开更多
基金financially supported by the National Natural Science Foundation of China(31372188,31471986)the Science and Technology Innovation Commission of Shenzhen Municipality(CXZZ20120614164555920)
文摘The Wnt/β-catenin signaling pathway plays a crucial role in the embryonic development of metazoans. Although the pathway has been studied extensively in many model animals, its function in amphioxus, the most primitive chordate, remains largely uncharacterized. To obtain basic data for functional analysis, we identified and isolated seven genes （Lrp5/6, Dvl, APC, Ckla, CklS, Gsk3β, and Gro） of the Wnt/β-catenin signaling pathway from the amphioxus （Branchiostoma floridae） genome. Phylogenetic analysis revealed that amphioxus had fewer members of each gene family than that found in vertebrates. Whole-mount in situ hybridization showed that the genes were maternally expressed and broadly distributed throughout the whole embryo at the cleavage and blastula stages. Among them, Dvl was expressed asymmetrically towards the animal pole, while the others were evenly distributed in all blastomeres. At the mid-gastrula stage, the genes were specifically expressed in the primitive endomesoderm, but displayed different patterns. When the embryo developed into the neurula stage, the gene expressions were mainly detected in either paraxial somites or the tail bud. With the development of the embryo, the expression levels further decreased gradually and remained only in some pharyngeal regions or the tail bud at the larva stage. Our results suggest that the Wnt/β-catenin pathway might be involved in amphioxus somite formation and posterior growth, but not in endomesoderm specification.
基金supported by the National Natural Science Foundation of China (Nos.31071110,30830023 and 31101631)the Scientific and Technical Innovation Committee of Shenzhen,China (No.CXZZ20120614164555920)
文摘Amphioxus, also called lancelet or cephalochordate, is a promising model organism owning to its particularly evolu- tionary position, simple genome content and comparable body plan to that of vertebrates （Holland et aL, 2004; Bertrand and Escriva, 2011）. However, use of amphioxus as a model or- ganism has been limited for many years because of lack of an efficient genomic modification method. Recently, several revolutionary gene targeting methods that could induce directed mutations, insertions and deletions at intended target sites, have been developed （Gaj et al., 2013）.
