Blunk Summer, Garcia-Verdugo Hector, O'Sullivan Sierra, Camp James, Haines Michael, Coalter Tara, Williams Terri A, Nagy Lisa M
Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA.
Biology Department, Trinity College, Hartford, CT 06106, USA.
Insects. 2023 Aug 4;14(8):691. doi: 10.3390/insects14080691.
and encode paralogous transcription factors found as a closely linked tandem duplication within holometabolous insects. mutants segment normally, then fail to maintain their segments. Loss of is viable, while loss of both genes results in asegmental larvae. Surprisingly, the knockdown of can result in the loss or fusion of the entire abdomen and knockdowns in show variable degrees of segmental loss. The consequence of losing or knocking down both paralogs on embryogenesis has not been studied beyond . To further investigate the relative functions of each paralog and the mechanism behind the segmental loss, double and single knockdowns of and were analyzed. The most common cuticular phenotype of the double knockdowns was small, limbless, and open dorsally, with all but a single, segmentally iterated row of bristles. Less severe knockdowns had fused segments and reduced appendages. The paralogs appear to act synergistically: the knockdown of either gene alone was typically less severe, with all limbs present, whereas the most extreme single knockdowns mimic the most severe double knockdown phenotype. Morphological abnormalities unique to either single gene knockdown were not found. expression was not affected in the knockdowns, but expression was unexpectedly increased midway through development. Thus, while the segmental expression of is broadly conserved within insects, the functions of and are evolving independently in different lineages.
并且编码在全变态昆虫中作为紧密连锁的串联重复出现的旁系同源转录因子。突变体正常分节，然后无法维持其分节。单个基因的缺失是可行的，而两个基因都缺失则导致无节幼虫。令人惊讶的是，基因的敲低可导致整个腹部的缺失或融合，并且在基因中的敲低表现出不同程度的分节缺失。除了之外，尚未研究失去或敲低两个旁系同源基因对胚胎发生的影响。为了进一步研究每个旁系同源基因的相对功能以及分节缺失背后的机制，对基因和的双敲低和单敲低进行了分析。双敲低最常见的表皮表型是小、无肢且背部开放，除了一排单一的、分节重复的刚毛外没有其他结构。不太严重的敲低有节段融合和附肢减少。这两个旁系同源基因似乎协同作用：单独敲低任何一个基因通常不太严重，所有肢体都存在，而最极端的单敲低模仿最严重的双敲低表型。未发现单个基因敲低特有的形态异常。基因的表达在敲低中不受影响，但基因的表达在发育中期意外增加。因此，虽然基因的分节表达在昆虫中广泛保守，但基因和的功能在不同谱系中独立进化。
