svp基因在果蝇副心肌细胞生长中的作用

果蝇心脏位于身体背部，是一个体节性重复的线性管状结构。在hedgehog（hh）基因的信号诱导下，seven-up（svp）基因调控果蝇的心脏发育，在每个体节的两个心肌细胞和两个副心肌细胞中表达。结果表明，在svp纯合突变体中，报告基因lacZ在心肌细胞中的表达图式正常，但在副心肌细胞中的表达图型明显异常，而且部分EPC细胞生长尺寸增加。某些体节的DA1肌肉祖细胞缺失，晚期突变体胚胎体壁肌肉细胞也呈现异常，表明基因svp的活性对果蝇副心肌细胞、DA1肌肉祖细胞和体壁肌肉细胞的分化是必须的，并且可能与EPC副心肌细胞的尺寸生长有关。

Role of svp in Drosophila Pericardial Cell Growth

The Drosophila dorsal vessel is a segmentally repeated linear organ,in which seven-up (svp) is expressed in two pairs of cardioblasts and two pairs of pericardial cells in each segment.Under the control of hedgehog (hh) signaling from the dorsal ectoderm,svp participates in diversifying cardioblast identities within each segment.In this experiment,the homozygous embryos of svp mutants exhibited an increase in cell size of Eve positive pericardial cells (EPCs) and a disarranged expression pattern,while the cardioblasts pattern of svp-lacZ expression was normal.In the meantime,the DA1 muscle founders were absent in some segments in svp mutant embryos,and the dorsal somatic muscle patterning was also severely damaged in the late stage mutant embryos, suggesting that svp is required for the differentiation of Eve-positive pericardial cells and DA1 muscle founders and may have a role in EPC cell growth.