Petschek J P, Perrimon N, Mahowald A P
Dev Biol. 1987 Jan;119(1):175-89. doi: 10.1016/0012-1606(87)90219-3.
Lack of zygotic expression of the l(1)giant locus (l(1)gt;3A1), produces embryos with defects in abdominal A5, 6, and 7 and within the head. Scanning electron microscopy at the time of segment formation reveals two regions of defects in the segmentation pattern: anteriorly the labial lobe and thoracic segments T1 and T2 are fused; posteriorly, abdominal segments A5-7 are disrupted. The mature embryo shows incomplete head involution and defects within A5-7; fusion of T1 and T2 is no longer observed. Localized cell death within neural and mesodermal tissues is observed at 7 hr of development; later ventral ganglia, A5-7, are missing. Double-mutant analyses of l(1)gt with maternal effect lethal mutations and mutations that generate homeotic, segment number, gap, or segment polarity phenotypes indicate that normal activity of l(1)gt is required for differentiation of two embryonic domains: one corresponding to labial, T1 and T2 segments, and the second corresponding to abdominal segments 5, 6, and 7.
缺乏l(1)giant基因座（l(1)gt;3A1）的合子表达会产生在腹部A5、6和7以及头部有缺陷的胚胎。在体节形成时进行扫描电子显微镜观察，发现体节模式存在两个缺陷区域：前部唇叶与胸节T1和T2融合；后部，腹部A5 - 7节段受到破坏。成熟胚胎显示头部内卷不完全以及A5 - 7区域存在缺陷；不再观察到T1和T2的融合。在发育7小时时观察到神经和中胚层组织内的局部细胞死亡；后期腹神经节A5 - 7缺失。对l(1)gt与母体效应致死突变以及产生同源异型、体节数量、间隙或体节极性表型的突变进行双突变分析表明，l(1)gt的正常活性对于两个胚胎区域的分化是必需的：一个对应唇叶、T1和T2节段，另一个对应腹部5、6和7节段。
