HOM-C/Hox genes and four interacting loci determine the morphogenetic properties of single cells in the nematode male tail.
HOM-C/Hox genes and four interacting loci determine the morphogenetic properties of single cells in the nematode male tail.
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发表时间：
1994-09
期刊：
影响因子：
4.6
通讯作者：
King Lau Chow;S. W. Emmons
中科院分区：
文献类型：
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作者：
King Lau Chow;S. W. Emmons
秀丽隐杆线虫雄性尾巴的交配结构包括一组9对两侧对称的感觉器官，称为射线。每条射线包括三个细胞，这些细胞是由18个表皮射线前体细胞表达的定型细胞亚系产生的。表皮中的模式形成机制指导了在表皮内特定位置的正确细胞器组装所必需的射线之间的形态发生差异的规范。这些射线差异的表达在我们之前描述的突变中被改变，导致偏移和融合射线。本研究表明秀丽隐杆线虫homc /Hox基因复合体的两个基因在模式形成机制中起作用。增加或减少mab-5（天线同源物）和egl-5（腹B同源物）的基因剂量会导致特定射线的移位和融合。这些变化被解释为射线恒等式的前或后变换。先前描述的基因突变是这些影响的主要修饰因子。这表明这些基因与mab-5和egl-5在相同的形态发生途径中起作用。包括细胞消融实验在内的一些证据表明，每种射线的身份是在射线谱系的末端细胞中自主指定的。因此，Mab-5和egl-5指定分化细胞的形态发生特性，而不改变细胞谱系或明显的细胞类型。修饰基因可能作用于mab-5和egl-5的上游，调控其表达。或者，它们可能作为辅助因子在通路的同一步骤中起作用，或者它们可能是靶基因。靶基因可能包括指定细胞识别的基因和控制射线细胞器组装的粘附分子。
The copulatory structure of the C. elegans male tail includes a set of nine bilaterally symmetrical pairs of sense organs known as rays. Each ray comprises three cells, which are generated by a stereotyped cell sublineage expressed by 18 epidermal ray precursor cells. A pattern formation mechanism in the epidermis guides the specification of morphogenetic differences between the rays necessary for correct organelle assembly at specific positions within the epidermis. Expression of these ray differences was altered in mutations we described previously, resulting in displaced and fused rays. Here we show that two genes of the C. elegans HOM-C/Hox gene complex play a role in the pattern formation mechanism. Increasing or decreasing the gene dosage of mab-5, an Antennapedia homolog, and egl-5, an Abdominal B homolog, results in displacement and fusion of specific rays. These changes are interpreted as anterior or posterior transformations in ray identities. Mutations in the genes previously described are dominant modifiers of these effects. This suggests that these genes act in the same morphogenetic pathway as mab-5 and egl-5. Several lines of evidence, including cell ablation experiments, argue that the identity of each ray is specified cell-autonomously in the terminal cells of the ray lineages. mab-5 and egl-5, therefore, specify the morphogenetic properties of differentiating cells, without change in cell lineage or apparent cell type. Modifier genes may act upstream of mab-5 and egl-5 to regulate their expression. Alternatively, they may act at the same step in the pathway, as cofactors, or they may be target genes. Target genes could include genes specifying cell recognition and adhesion molecules governing ray organelle assembly.