Chisholm Andrew D, Hsiao Tiffany I
Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA.
Wiley Interdiscip Rev Dev Biol. 2012 Nov-Dec;1(6):861-78. doi: 10.1002/wdev.79. Epub 2012 Jun 19.
The skin of the nematode Caenorhabditis elegans is composed of a simple epidermal epithelium and overlying cuticle. The skin encloses the animal and plays central roles in body morphology and physiology; its simplicity and accessibility make it a tractable genetic model for several aspects of skin biology. Epidermal precursors are specified by a hierarchy of transcriptional regulators. Epidermal cells form on the dorsal surface of the embryo and differentiate to form the epidermal primordium, which then spreads out in a process of epiboly to enclose internal tissues. Subsequent elongation of the embryo into a vermiform larva is driven by cell shape changes and cell fusions in the epidermis. Most epidermal cells fuse in mid-embryogenesis to form a small number of multinucleate syncytia. During mid-embryogenesis the epidermis also becomes intimately associated with underlying muscles, performing a tendon-like role in transmitting muscle force. Post-embryonic development of the epidermis involves growth by addition of new cells to the syncytia from stem cell-like epidermal seam cells and by an increase in cell size driven by endoreplication of the chromosomes in epidermal nuclei.
秀丽隐杆线虫的皮肤由简单的表皮上皮和覆盖其上的角质层组成。皮肤包裹着动物，在身体形态和生理方面发挥着核心作用；其简单性和易接近性使其成为皮肤生物学多个方面易于处理的遗传模型。表皮前体由转录调节因子的层次结构指定。表皮细胞在胚胎的背表面形成并分化形成表皮原基，然后在外包过程中扩散以包围内部组织。随后胚胎伸长成为蠕虫状幼虫是由表皮中的细胞形状变化和细胞融合驱动的。大多数表皮细胞在胚胎发育中期融合形成少量多核合胞体。在胚胎发育中期，表皮也与下面的肌肉紧密相连，在传递肌肉力量方面发挥类似肌腱的作用。表皮的胚胎后发育涉及通过从干细胞样表皮缝细胞向合胞体添加新细胞以及通过表皮细胞核中染色体的内复制驱动的细胞大小增加来实现生长。
