Sorting of the initial cell types in Dictyostelium is dependent on the tipA gene.
Sorting of the initial cell types in Dictyostelium is dependent on the tipA gene.
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盘基网柄菌中初始细胞类型的分选取决于tipA 基因。
DOI：
10.1006/dbio.1997.8538
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Loomis,WF
中科院分区：
文献类型：
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作者：
Stege,JT;Shaulsky,G;Loomis,WF
在盘基网柄藻发育开始后约8小时，一些随机分散的细胞表达前柄特异性基因，随后分选到聚集体的顶部，在那里它们形成尖端。在分化成支持成熟子实体中的孢子球的柄之前，尖端伸长并形成迁移的蛞蝓的前部。使用REMI诱变，我们分离出一个突变株，AK 244，其中最初的聚集体细分，得到一个高度乳头状表面。这种突变体不能形成蛞蝓，似乎在前柄细胞的分选方面有缺陷。被破坏的基因，tipA，编码一种新的83-kDa的蛋白质，并优先表达在PST-O细胞后，细胞类型已分选出来。缺乏TipA的突变株以降低的水平表达前茎特异性基因，并且形成很少的孢子。这些缺陷不能通过在野生型细胞存在下开发突变细胞来克服。因此，TipA在发育的早期阶段以细胞自主的方式起作用。使用携带报告构建体的菌株，我们发现表达前茎标记的突变体细胞仍然分散在聚集体中。前孢子细胞似乎进行分选，使得基底不含表达细胞类型特异性标记的细胞。即使在发育20小时后，当野生型细胞正在经历终末分化时，前茎细胞intipA−突变体形成非常小的团块，其中大多数未能分选到聚集体的外围或顶部。TipA基因似乎在初始细胞类型的分选中起重要作用。
About 8 hr after the initiation of development inDictyostelium discoideum,a few randomly scattered cells express prestalk specific genes and subsequently sort out to the top of the aggregate where they form a tip. The tip elongates and forms the anterior of the migrating slug before differentiating into a stalk which supports the ball of spores in a mature fruiting body. Using REMI mutagenesis we isolated a mutant strain, AK244, in which the initial aggregate subdivides to give a highly papillated surface. This mutant fails to form slugs and appears to have a defect in sorting of prestalk cells. The disrupted gene,tipA,encodes a novel 83-kDa protein and is preferentially expressed in PST-O cells after the cell types have sorted out. Mutant strains that lack TipA express the prestalk-specific geneecmAat reduced levels and form very few spores. These defects cannot be overcome by developing the mutant cells in the presence of wild-type cells. Thus, TipA acts in a cell-autonomous manner at an early stage in development. Using strains carrying reporter constructs, we found that mutant cells expressing a prestalk marker remain dispersed in the aggregates. Prespore cells appear to sort such that the base is free of cells expressing cell-type-specific markers. Even after 20 hr of development, when wild-type cells are undergoing terminal differentiation, prestalk cells intipA−mutants form very small clumps, most of which fail to sort to the periphery or the tops of aggregates. ThetipAgene appears to play an essential role in the sorting of the initial cell types.