Development and evolution of chordate cartilage.
Development and evolution of chordate cartilage.
复制标题
脊索动物软骨的发育和进化。
DOI：
10.1002/jez.b.21157
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Swalla,BillieJ
中科院分区：
文献类型：
--
作者：
Rychel,AmandaL;Swalla,BillieJ
后口动物是一个单系动物类群，包含脊椎动物、文昌鱼、被囊动物、半索动物、棘皮动物和异形龟类。这六个现存类群中的四个——脊椎动物、文昌鱼、被囊动物和半索动物——都有咽鳃缝。除被囊动物外，所有具有咽鳃缝的后口动物群也具有支撑咽开口的咽骨骼。我们之前发现半索动物和头索动物的咽软骨含有类似于脊椎动物II型胶原的纤维状胶原蛋白，但与脊椎动物软骨不同的是，无脊椎动物后口动物软骨是无细胞的。我们发现 SoxE 和纤维状胶原在邻近软骨形成处的咽内胚层细胞中表达。这些相同的内胚层上皮细胞还表达 Pax1/9，这是脊椎动物、文昌鱼、被囊动物和半索动物中咽内胚层的标志物。头索类纤维状胶原的原位实验也显示在咽内胚层、外胚层和鳃条内衬的中胚层体腔囊中表达。这些结果表明，半索动物中咽内胚层细胞负责软骨的分泌，而在文昌鱼中，鳃条周围的所有咽细胞、外胚层、内胚层和中胚层可能负责软骨的形成。我们认为内胚层分泌主要是后口动物制造咽软骨的祖先模式。后来，神经嵴的进化起源使得在脊椎动物中发现的新的迁移性神经嵴细胞群中能够共同选择分泌咽软骨基质的基因网络。过期。动物园。 (Mol. Dev. Evol.) 308B:325–335, 2007。© 2007 Wiley-Liss, Inc.
Deuterostomes are a monophyletic group of animals containing vertebrates, lancelets, tunicates, hemichordates, echinoderms, and xenoturbellids. Four out of these six extant groups—vertebrates, lancelets, tunicates, and hemichordates—have pharyngeal gill slits. All groups of deuterostome animals that have pharyngeal gill slits also have a pharyngeal skeleton supporting the pharyngeal openings, except tunicates. We previously found that pharyngeal cartilage in hemichordates and cephalochordates contains a fibrillar collagen protein similar to vertebrate type II collagen, but unlike vertebrate cartilage, the invertebrate deuterostome cartilages are acellular. We foundSoxEand fibrillar collagen expression in the pharyngeal endodermal cells adjacent to where the cartilages form. These same endodermal epithelial cells also expressPax1/9, a marker of pharyngeal endoderm in vertebrates, lancelets, tunicates, and hemichordates. In situ experiments with a cephalochordate fibrillar collagen also showed expression in pharyngeal endoderm, as well as the ectoderm and the mesodermal coelomic pouches lining the gill bars. These results indicate that the pharyngeal endodermal cells are responsible for secretion of the cartilage in hemichordates, whereas in lancelets, all the pharyngeal cells surrounding the gill bars, ectodermal, endodermal, and mesodermal may be responsible for cartilage formation. We propose that endoderm secretion was primarily the ancestral mode of making pharyngeal cartilages in deuterostomes. Later the evolutionary origin of neural crest allowed co‐option of the gene network for the secretion of pharyngeal cartilage matrix in the new migratory neural crest cell populations found in vertebrates.J. Exp. Zool. (Mol. Dev. Evol.) 308B:325–335, 2007. © 2007 Wiley‐Liss, Inc.