Kim Jiwon, Shim Sangwoo, Choi Sun-Cheol, Han Jin-Kwan
Division of Molecular and Life Sciences, Pohang University of Science and Technology, San 31 Hyoja Dong, Pohang, Kyungbuk 790-784, South Korea.
Gene Expr Patterns. 2003 May;3(2):219-23. doi: 10.1016/s1567-133x(02)00073-x.
The GTPase activating proteins (GAPs) specific for Rho family GTPases serve as either negative regulators or downstream effectors of Rho-GTPases through their ability to interact with specific Rho proteins and additional cytosolic factors. Here we report cloning and expression of a novel Xenopus Rho-GTPase activating protein cDNA designated as XrGAP. It encodes a protein of 1902 amino acids that contains a PDZ domain, a PH motif and a Rho-GAP domain. Sequence analysis shows that XrGAP protein shares 60% overall amino acids identity with a human Rho-GTPase activating protein (ARHGAP10) that is highly expressed in the brain. Northern blot and RT-PCR analysis show that a single XrGAP transcript is maternally expressed and gradually decreases afterwards. Whole-mount in situ hybridization shows that maternal XrGAP transcripts are specifically expressed in the animal hemisphere of the eggs and blastula stage embryos. During gastrulation, XrGAP is detected in the prospective neuroectoderm and the mesoderm. At neurula stages, the expression is in the neural regions including the neural folds, eye analgen and neural crest cells, and subsequently restricted to notochord, developing brain, spinal cord, eye, branchial arches, and otic vesicle at tailbud stages.
对Rho家族GTP酶具有特异性的GTP酶激活蛋白（GAPs），通过其与特定Rho蛋白及其他胞质因子相互作用的能力，充当Rho - GTP酶的负调节因子或下游效应器。在此，我们报告了一种名为XrGAP的非洲爪蟾新型Rho - GTP酶激活蛋白cDNA的克隆与表达。它编码一个含1902个氨基酸的蛋白质，该蛋白质包含一个PDZ结构域、一个PH基序和一个Rho - GAP结构域。序列分析表明，XrGAP蛋白与在脑中高表达的人类Rho - GTP酶激活蛋白（ARHGAP10）总体氨基酸同一性为60%。Northern印迹和RT - PCR分析显示，单个XrGAP转录本在母源表达，随后逐渐减少。整胚原位杂交显示，母源XrGAP转录本在卵和囊胚期胚胎的动物半球特异性表达。在原肠胚形成过程中，XrGAP在前神经外胚层和中胚层中被检测到。在神经胚阶段，表达出现在包括神经褶、眼原基和神经嵴细胞在内的神经区域，随后在尾芽阶段局限于脊索、发育中的脑、脊髓、眼、鳃弓和耳泡。
