Mechanisms of regeneration of insect imaginal discs.

1.Sarcophaga成像盘在体外再生时的位置值的恢复：将表达WG基因的Sarcophaga成像盘的1/4扇区取出，并将其记忆部分在2.5×10~(-8)&gt；M~(20-羟基蜕皮激素)的存在下培养，其形态发生了恢复。在这里，我们分离了Sarcophaga WG基因的cDNA，并分析了当剩余的成像盘在20-羟基蜕皮激素存在下培养时，WG表达所揭示的丢失的位置值是否被恢复。结果表明，WG基因在再生节段有表达，说明在体外盘的再生和体内再生涉及位置值的恢复。2.定位于美洲蟑螂再生腿中的凝集素基因的克隆和表达分析。Amer…再生腿中瞬时出现两种体液凝集素，分别为26-kDa凝集素和再生凝集素更多的美国蟑螂。其中，26 kDa的凝集素在再生中期定位于再生腿的表皮，而再生凝集素在再生后期定位于再生肌细胞周围。在这项研究中，我们对这些凝集素的cDNA进行了异构化，并确定了它们的一级结构。结果发现，这些凝集素是C型(钙依赖)凝集素，与Eact Other的序列同源性约为50%。这些结果表明，这些凝集素属于相同的蛋白质家族，在腿部再生中发挥不同的作用。研究发现，再生凝集素基因在再生的表皮中瞬时表达，提示再生凝集素通过表皮合成和分泌，以旁分泌的方式参与肌肉细胞的形成。这是首次发现与昆虫再生有关的分子(20-羟基蜕皮素和体液凝集素)，为更好地理解器官再生的分子机制提供了重要线索。较少

1. Restoration of positional values of Sarcophaga imaginal discs on regeneration in vitro.When the 1/4 sectors of imaginal discs of Sarcophaga expressing wingles (wg) gene are removed and the remeining parts are cultured in the presence of 2.5 x 10^<-8>M 20-hydroxyecdyson, restoration of their morphology occurrs. Here, we isolated a cDNA for the Sarcophaga wg gene, and analyzed whether the lost positional values revealed by wg expression were restored when the remaining parts of imaginal discs were cultured in the presence of 20-hydroxyecdyson. As results, expression of the wg gene was detected in the regenrated areas, indicating that regeneration of imaginal discs in vitro minics in vivo regeneration in that it involves restoration of positional values.2.cDNA cloning and analysis of expression of the gene for lectins that localize in the regenerating legs of American cockroach.Two humoral lectins, termed 26-kDa lectin and regenectin, appear transiently in the regenerating legs of Amer … More ican cockroach. Among them, 26-kDa lectin localizes around epidermis of the regenerating legs in the middle stage of regeneratin, whereas regenectin localizes around regenetating muscle cells in the late stage. In this study, we isoalted cDNAs for these lectins and determined their primary structures. As results, these lectins were found to be C-type (Ca^<2+>-dependent) lectins and shares about 50% sequence identities with eact other. these results suggest that these lectins belong to the same protein family and play different roles in leg regeneration. The gene for regenectin was found to express transiently in the regenerating epidermis, suggesting that it functions in the formation of muscle cells in a paracrine manner by synthesized and secreted by the epidermis.This is the first instance that identified molecules (20-hydroxyecdyson and humoral lectins) that is involved in the regeneration in insects and woud be an important clue to better undrstand the molecular mechanisms of organ regeneration. Less