Hassel M, Bridge D M, Stover N A, Kleinholz H, Steele R E
Zoologie II, Universität Heidelberg, INF 230, D-69120 Heidelberg, Germany.
Dev Genes Evol. 1998 Feb;207(8):502-14. doi: 10.1007/s004270050141.
Several studies have provided strong, but indirect evidence that signalling through pathways involving protein kinase C (PKC) plays an important role in morphogenesis and patterning in Hydra. We have cloned a gene (HvPKC2) from Hydra vulgaris which encodes a member of the nPKC subfamily. In adult polyps, HvPKC2 is expressed at high levels in two locations, the endoderm of the foot and the endoderm of the hypostomal tip. Increased expression of HvPKC2 is an early event during head and foot regeneration, with the rise in expression being restricted to the endodermal cells underlying the regenerating ends. No upregulation is observed if regenerates are cut too close to the head to form a foot. Elevated expression of HvPKC2 is also observed in the endoderm underlying lithium-induced ectopic feet. A dynamic and complex pattern of expression is seen in developing buds. Regeneration of either head or foot is accompanied by an increase in the amount of PKC in both soluble and particulate fractions. An increase in the fraction of PKC activity which is membrane-bound is specifically associated with head regeneration. Taken together these data suggest that patterning of the head and foot in Hydra is controlled in part by the level of HvPKC2 expression, whilst head formation is accompanied by an in vivo activation of both calcium-dependent and independent PKC isoforms.
多项研究提供了有力但间接的证据，表明通过涉及蛋白激酶C（PKC）的信号通路在水螅的形态发生和模式形成中发挥重要作用。我们从普通水螅中克隆了一个基因（HvPKC2），它编码nPKC亚家族的一个成员。在成年水螅体中，HvPKC2在两个部位高表达，即足部的内胚层和口柄顶端的内胚层。HvPKC2表达增加是头部和足部再生过程中的早期事件，其表达升高仅限于再生末端下方的内胚层细胞。如果再生体切割得离头部太近而形成足部，则未观察到上调现象。在锂诱导的异位足部下方的内胚层中也观察到HvPKC2表达升高。在发育中的芽中可见动态且复杂的表达模式。头部或足部的再生均伴随着可溶性和颗粒性部分中PKC量的增加。膜结合的PKC活性部分增加与头部再生特别相关。综合这些数据表明，水螅头部和足部的模式形成部分受HvPKC2表达水平的控制，而头部形成伴随着钙依赖性和非依赖性PKC同工型的体内激活。
