Aspland S E, White R A
Department of Anatomy, University of Cambridge, UK.
Development. 1997 Feb;124(3):741-7. doi: 10.1242/dev.124.3.741.
The extradenticle protein is a homeodomain transcription factor which has an important role regulating the DNA-binding specificity of homeotic selector proteins. We have made a monoclonal antibody against extradenticle and have studied the expression of the protein in the embryo and in imaginal discs. We find that extradenticle is initially uniformly distributed as expected but strikingly is excluded from nuclei until gastrulation. During the extended germ band stage the protein remains predominantly cytoplasmic and does not accumulate in nuclei until germ band retraction. Nuclear accumulation occurs in a highly spatially regulated pattern. In the imaginal discs the nuclear accumulation of extradenticle is also spatially regulated and, in the wing and leg discs, distal regions exhibit cytoplasmic extradenticle whereas proximally the protein is nuclear. We suggest that this regulation of the sub-cellular localisation of extradenticle is important for the interactions between extradenticle and the homeotic selector proteins and that extradenticle is not simply a ubiquitously available cofactor.
额外齿蛋白是一种同源异型结构域转录因子，在调节同源异型选择蛋白的DNA结合特异性方面发挥着重要作用。我们制备了一种针对额外齿蛋白的单克隆抗体，并研究了该蛋白在胚胎和成虫盘的表达情况。我们发现，额外齿蛋白最初如预期那样均匀分布，但直到原肠胚形成之前，它都显著地被排除在细胞核之外。在延长胚带阶段，该蛋白主要保留在细胞质中，直到胚带回缩才会在细胞核中积累。细胞核积累以高度空间调节的模式发生。在成虫盘中，额外齿蛋白的细胞核积累也受到空间调节，在翅和腿盘中，远端区域显示细胞质中的额外齿蛋白，而近端则是细胞核中的该蛋白。我们认为，额外齿蛋白亚细胞定位的这种调节对于额外齿蛋白与同源异型选择蛋白之间的相互作用很重要，并且额外齿蛋白并非仅仅是一种普遍存在的辅助因子。
