Data from: New insights for Drosophila GAGA factor in larvae

GAGA factor plays important roles during Drosophila embryogenesis and its maternal contribution is essential for early development. Here, the role of GAGA factor was studied in 3rd instar larvae using depletion and overexpression conditions in wing disk and transcriptome analysis. We found that genes changing expression were different to those previously described using GAGA mutants in embryos. No apparent phenotypes on GAGA depletion could usually be observed at larval stages in imaginal disks but a strong effect on salivary gland polytene chromosomes was observed. In the adult, GAGA depletion produced many defects like abnormal cell proliferation in the wing, impaired dorsal closure, and resulted in homeotic transformation of abdominal segment A5 in the adult. Unexpectedly, no effects on Ultrabithorax expression were observed. Short overexpression of GAGA factor in 3rd instar larvae also resulted in activation of a set of genes not previously described to be under GAGA regulation, and in lethality at pupa. Our results suggest a little contribution of GAGA factor on gene transcription in wing disks and a change of the genes regulated in comparison to embryo. GAGA factor activity thus correlates with the global changes in gene expression that take place at the embryo-to-larva and, later, at the larva-to-pupa transitions.

GAGA因子(GAGA factor)在果蝇胚胎发生过程中发挥关键作用，其母源贡献对早期发育不可或缺。本研究以三龄幼虫为研究对象，通过翅成虫盘的基因敲降与过表达体系结合转录组分析，探究了GAGA因子的功能。我们发现，表达发生改变的基因与此前在胚胎中使用GAGA突变体所报道的基因存在差异。在幼虫阶段的成虫盘中，GAGA因子敲降通常未观察到明显表型，但在唾液腺多线染色体中却观测到了显著效应。在成虫体内，GAGA因子敲降会引发多种缺陷：包括翅部细胞增殖异常、背闭合受损，还会导致成虫腹部体节A5发生同源异型转化。令人意外的是，本研究未观测到对超胸基因(Ultrabithorax)表达的影响。在三龄幼虫中短期过表达GAGA因子，同样会激活一批此前未被报道处于GAGA因子调控之下的基因，并导致蛹期致死。我们的研究结果表明，GAGA因子在翅成虫盘的基因转录中仅发挥微弱作用，且相较于胚胎阶段，其调控的基因谱发生了改变。因此，GAGA因子的活性与胚胎向幼虫转变以及后续幼虫向蛹转变过程中发生的全局基因表达变化密切相关。