Wasser Martin, Bte Osman Zalina, Chia William
Bioinformatics Institute, Department of Imaging Informatics, Republic of Singapore.
Dev Biol. 2007 Jul 15;307(2):380-93. doi: 10.1016/j.ydbio.2007.05.001. Epub 2007 May 6.
Metamorphosis involves the destruction of larval, the formation of adult and the transformation of larval into adult tissues. In this study, we demonstrate the role of the Drosophila nuclear proteins EAST and Chromator in tissue destruction and remodeling. To better understand the function of east, we performed a yeast two-hybrid screen and identified the euchromatin associated protein Chromator as a candidate interactor. To analyze the functional significance of our two-hybrid data, we generated a set of novel pupal lethal Chro alleles by P-element excision. The pupal lethal Chro mutants resemble lethal east alleles as homozygous mutants develop into pharates with normal looking body parts, but fail to eclose. The eclosion defect of the Chro alleles is rescued in an east heterozygous background, indicating antagonistic genetic interactions between the two genes. Live cell imaging was applied to study muscle development during metamorphosis. Consistent with the eclosion defects, mutant pharates of both genes show loss and abnormal differentiation of adult eclosion muscles. The two genes have opposite effects on the destruction of larval muscles in metamorphosis. While Chro mutants show incomplete histolysis, muscles degenerate prematurely in east mutants. Moreover east mutants affect the remodeling of abdominal larval muscles into adult eclosion muscles. During this process, loss of east interferes with the spatial coordination of thinning of the larval muscles. Overexpression of EAST-GFP can prevent the disintegration of polytene chromosomes during programmed cell death. We propose that Chro activates and east inhibits processes and genes involved in tissue destruction and remodeling.
变态发育涉及幼虫组织的破坏、成虫组织的形成以及幼虫组织向成虫组织的转变。在本研究中，我们证明了果蝇核蛋白EAST和Chromator在组织破坏和重塑中的作用。为了更好地理解east的功能，我们进行了酵母双杂交筛选，并确定常染色质相关蛋白Chromator为候选相互作用蛋白。为了分析我们双杂交数据的功能意义，我们通过P元素切除产生了一组新的蛹期致死性Chro等位基因。蛹期致死性Chro突变体类似于致死性east等位基因，因为纯合突变体发育为外观正常身体部位的滞育蛹，但无法羽化。Chro等位基因的羽化缺陷在east杂合背景中得到挽救，表明这两个基因之间存在拮抗遗传相互作用。应用活细胞成像技术研究变态发育过程中的肌肉发育。与羽化缺陷一致，这两个基因的突变滞育蛹均显示成虫羽化肌的丧失和异常分化。这两个基因在变态发育过程中对幼虫肌肉的破坏具有相反的作用。虽然Chro突变体显示不完全组织溶解，但在east突变体中肌肉过早退化。此外，east突变体影响腹部幼虫肌肉向成虫羽化肌的重塑。在此过程中，east的缺失干扰了幼虫肌肉变薄的空间协调。EAST-GFP的过表达可以在程序性细胞死亡期间防止多线染色体的解体。我们提出，Chro激活而east抑制参与组织破坏和重塑的过程和基因。
