Regulation of the genes of the bithorax complex in Drosophila.
Regulation of the genes of the bithorax complex in Drosophila.
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DOI：
10.1007/978-1-4020-6345-9_13
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发表时间：
1985
期刊：
影响因子：
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通讯作者：
E. Lewis
中科院分区：
文献类型：
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作者：
E. Lewis
方法为了识别BX-C内尽可能多的功能单位，已经设计了两个基因筛查。第一个，或MCP筛查，涉及寻找显性功能获得突变体错体色素沉着(Mcp)的返回体。Mcp表型包括第四腹段(A4)向第五腹段(A5)的强烈转变，并且很容易在雄性身上得分，因为它们在A4、A5和A6上有实心的黑色色素沉着，而野生型雄性只在A5和A6上有这种色素沉着。M.Crosby发现并推广了MCP(见Lewis 1978)，他表明可以诱导几种类型的逆转株，其中一种是由于腹下-5(IAB-5)基因功能丧失所致。在后一种情况下，突变体被证明是第二个突变体，IAB-5C7，非常接近MCP的右侧(M.Crosby，Upub.)；这个突变体和其他几个突变体已经用分子方法定位(Kch等人。1985年)。为了应用MCP筛查，一种方法是将Mcp纯合子(根据需要，可以是雄性或FEMA Les)和配对突变为野生型。然后，F1男性被评分为部分L或完全消失的A4上的男性类型色素沉着。第二种，或称全局重排(GR)筛查，旨在检测几乎所有在BX-C内有一个断裂点的总染色体重排。这一筛选采用了两个显性突变体的顺式排列，Contrabithorax
METHODSTwo genetic screens have been devised for the purpose of identify ing as many as possible of the functional units within the BX-C. The first, or MCP screen, involves searching for revertants of the dominant gain-of-function mutant Miscadastral pigmentation (Mc p). The Mc p phenotype consists of a strong transformation of the fourth abdominal segment (A4) toward the fift h abdominal segment (A5) and is readily scored in males as they have solid black pigmentation on A4, A5, and A6, whereas wild-type males have such pigmentation only on A5 and A6. M. Crosby, who found and ma y pped Mcp (see Lewis 1978), showed that several types of revertants can be induced, one of which results from a loss of function in an adj oining infra-abdominal-5 (iab-5) gene. In this latter case, the revertant proved to be a second mutant, iab-5C7, very close to the right of Mcp (M. Crosby, un publ.); this and several other revertants have been mapped by molecular methods (Karch et al. 1985). To apply the MCP screen, one mutagenizes Mc p homozygotes (either males or fema les, as desired) and mates to wild type. The F1 males are then scored for partia f l or complete loss of the maletype pigmentation on A4. The second, or global rearrangement (GR) screen, is designed to detect virtually all gross chromosomal rearrangements that have one breakage point within the BX-C. This screen employs a cis-arrangement of two dominant mutants, Contrabithorax