Bettinger J C, Euling S, Rougvie A E
Department of Genetics and Cell Biology, University of Minnesota, St Paul 55108, USA.
Development. 1997 Nov;124(21):4333-42. doi: 10.1242/dev.124.21.4333.
Caenorhabditis elegans vulval development culminates during exit from the L4-to-adult molt with the formation of an opening through the adult hypodermis and cuticle that is used for egg laying and mating. Vulva formation requires the heterochronic gene lin-29, which triggers hypodermal cell terminal differentiation during the final molt. lin-29 mutants are unable to lay eggs or mate because no vulval opening forms; instead, a protrusion forms at the site of the vulva. We demonstrate through analysis of genetic mosaics that lin-29 is absolutely required in a small subset of lateral hypodermal seam cells, adjacent to the vulva, for wild-type vulva formation and egg laying. However, lin-29 function is not strictly limited to the lateral hypodermis. First, LIN-29 accumulates in many non-hypodermal cells with known roles in vulva formation or egg laying. Second, animals homozygous for one lin-29 allele, ga94, have the vulval defect and cannot lay eggs, despite having a terminally differentiated adult lateral hypodermis. Finally, vulval morphogenesis and egg laying requires lin-29 activity within the EMS lineage, a lineage that does not generate hypodermal cells.
秀丽隐杆线虫的阴门发育在从L4期向成虫蜕皮的过程中达到顶点，此时会在成虫的皮下组织和角质层形成一个开口，用于产卵和交配。阴门形成需要异时性基因lin-29，它在最后一次蜕皮期间触发皮下细胞的终末分化。lin-29突变体无法产卵或交配，因为没有形成阴门开口；相反，在阴门部位会形成一个突起。我们通过对遗传嵌合体的分析表明，对于野生型阴门形成和产卵，lin-29在阴门附近的一小部分侧皮下缝合细胞中是绝对必需的。然而，lin-29的功能并不严格局限于侧皮下组织。首先，LIN-29在许多在阴门形成或产卵中具有已知作用的非皮下细胞中积累。其次，一个lin-29等位基因ga94的纯合动物，尽管有终末分化的成虫侧皮下组织，但仍有阴门缺陷且无法产卵。最后，阴门形态发生和产卵需要EMS谱系内的lin-29活性，EMS谱系不产生皮下细胞。
