Schulze K L, Bellen H J
Division of Neuroscience, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030, USA.
Genetics. 1996 Dec;144(4):1713-24. doi: 10.1093/genetics/144.4.1713.
The role of the Drosophila homologue of syntaxin-1A (syx) in neurotransmission has been extensively studied. However, developmental Northern analyses and in situ hybridization experiments show that SYX mRNA is expressed during all stages and in many tissues. We have isolated new mutations in syx that reveal roles for syx outside the nervous system. In the ovary, SYX is present in the germarium, but it is predominantly localized to nurse cell membranes. Mitotic recombination experiments in the germline show SYX is essential for oogenesis and may participate in membrane biogenesis in the nurse cells. In the early embryo, a large contribution of maternally deposited RNA is present, and the protein is localized at cell membranes during cellularization. After the maternal contribution is depleted, zygotically produced SYX assists secretion events occurring late in embryogenesis, such as cuticle deposition and neurotransmitter release. However, SYX is also required in larval imaginal discs, as certain hypomorphic mutant combinations exhibit rough eyes and wing notch defects indicative of cell death. Furthermore, recombinant clones that lack syx cause cell lethality in the developing eye. We propose that, similar to its roles in cuticle secretion and neurotransmitter release, SYX may mediate membrane assembly events throughout Drosophila development.
Syntaxin-1A（syx）的果蝇同源物在神经传递中的作用已得到广泛研究。然而，发育Northern分析和原位杂交实验表明，SYX mRNA在所有阶段以及许多组织中均有表达。我们分离出了syx中的新突变，这些突变揭示了syx在神经系统之外的作用。在卵巢中，SYX存在于生殖腺中，但主要定位于滋养细胞膜。生殖系中的有丝分裂重组实验表明，SYX对卵子发生至关重要，可能参与滋养细胞中的膜生物合成。在早期胚胎中，存在大量母源沉积的RNA，并且在细胞化过程中该蛋白定位于细胞膜。母源贡献耗尽后，合子产生的SYX协助胚胎发育后期发生的分泌事件，如表皮沉积和神经递质释放。然而，幼虫成虫盘也需要SYX，因为某些亚等位基因突变组合表现出粗糙的眼睛和翅膀缺口缺陷，表明细胞死亡。此外，缺乏syx的重组克隆在发育中的眼睛中会导致细胞致死。我们提出，与其在表皮分泌和神经递质释放中的作用类似，SYX可能在果蝇发育过程中介导膜组装事件。
