Lyons Deirdre C, Martik Megan L, Saunders Lindsay R, McClay David R
Department of Biology, Duke University, 124 Science Drive, Box 90338, Durham, NC 27708, USA.
Department of Biology, Duke University, 124 Science Drive, Box 90338, Durham, NC 27708, USA
Integr Comp Biol. 2014 Oct;54(4):723-33. doi: 10.1093/icb/icu087. Epub 2014 Jul 9.
The sea urchin larva is shaped by a calcite endoskeleton. That skeleton is built by 64 primary mesenchyme cells (PMCs) in Lytechinus variegatus. The PMCs originate as micromeres due to an unequal fourth cleavage in the embryo. Micromeres are specified in a well-described molecular sequence and enter the blastocoel at a precise time using a classic epithelial-mesenchymal transition. To make the skeleton, the PMCs receive signaling inputs from the overlying ectoderm, which provides positional information as well as control of the growth of initial skeletal tri-radiates. The patterning of the skeleton is the result both of autonomous inputs from PMCs, including production of proteins that are included in the skeletal matrix, and of non-autonomous dynamic information from the ectoderm. Here, we summarize the wealth of information known about how a PMC contributes to the skeletal structure. The larval skeleton is a model for understanding how information encoded in DNA is translated into a three-dimensional crystalline structure.
海胆幼虫由方解石内骨骼塑造而成。在多色刺海胆中，该骨骼由64个初级间充质细胞（PMC）构建。由于胚胎中第四次卵裂不均等，PMC最初作为小分裂球产生。小分裂球通过一个描述详尽的分子序列被指定，并在精确的时间利用经典的上皮-间充质转化进入囊胚腔。为了构建骨骼，PMC接收来自上方外胚层的信号输入，外胚层提供位置信息以及对初始骨骼三叉形结构生长的控制。骨骼的图案形成既是PMC自主输入的结果，包括产生包含在骨骼基质中的蛋白质，也是来自外胚层的非自主动态信息的结果。在这里，我们总结了关于PMC如何对骨骼结构做出贡献的丰富信息。幼虫骨骼是理解DNA中编码的信息如何转化为三维晶体结构的模型。
