Kuhn D T, Packert G
Department of Biological Sciences, University of Central Florida, Orlando 32816.
Dev Biol. 1988 Jan;125(1):8-18. doi: 10.1016/0012-1606(88)90054-1.
The homeotic mutants tuh-3, SGA62, I127, and R17.32 are located in the abdominal portion of the bithorax complex in Drosophila melanogaster. The genes act as semidominants in the head, causing a gain of expression of leg, genitalia, tergite, or combinations of the structures. SGA62, tuh-3, and I127 additionally act as recessives in the posterior abdomen, causing a loss of these functions. Each mutant has its own focus of expression in the head region. I127 and tuh-3 can cause head defects only in the presence of the recessive maternal effect allele tuh-1h, while SGA62 and R17.32 cause head defects in the absence of this maternal effect. In the presence of the dominant tuh-1g maternal effect allele, the tuh-3 and I127 heads are normal. However, these flies now show a genital disc defect. SGA62 homozygotes have abdominal segments 6 and 7 transformed into a more anterior segment irrespective of the maternal effect in force. R17.32 appears to map to the abd-A domain, while SGA62, I127, and tuh-3 belong to Abd-B. SGA62 is located in the morphogenetic element of Abd-B, while I127 has characteristics of mutants affecting both the morphogenetic and regulatory elements of Abd-B. The tuh-3 mutant is within the regulatory element. The maternal effect alleles appear to interact specifically with mutants in the regulatory region of Abd-B.
同源异型突变体tuh-3、SGA62、I127和R17.32位于黑腹果蝇双胸复合体的腹部区域。这些基因在头部表现为半显性，导致腿部、生殖器、背板或这些结构组合的表达增加。此外，SGA62、tuh-3和I127在腹部后部表现为隐性，导致这些功能丧失。每个突变体在头部区域都有自己的表达焦点。I127和tuh-3只有在隐性母体效应等位基因tuh-1h存在时才会导致头部缺陷，而SGA62和R17.32在没有这种母体效应时会导致头部缺陷。在显性tuh-1g母体效应等位基因存在的情况下，tuh-3和I127的头部是正常的。然而，这些果蝇现在表现出生殖器盘缺陷。SGA62纯合子的腹部第6和第7节会转变为更靠前的节段，而与当时存在的母体效应无关。R17.32似乎定位在abd-A结构域，而SGA62、I127和tuh-3属于Abd-B。SGA62位于Abd-B的形态发生元件中，而I127具有影响Abd-B形态发生和调控元件的突变体特征。tuh-3突变体位于调控元件内。母体效应等位基因似乎与Abd-B调控区域的突变体发生特异性相互作用。
