Kashef Jubin, Diana Tanja, Oelgeschläger Michael, Nazarenko Irina
Zoological Institute, Department of Cell and Developmental Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany.
Gene Expr Patterns. 2013 Jan-Feb;13(1-2):1-11. doi: 10.1016/j.gep.2012.08.001. Epub 2012 Aug 24.
Tetraspanins comprise a large family of integral membrane proteins involved in the regulation of cell adhesion, migration and fusion. In humans it consists of 33 members divided in four subfamilies. Here, we examined the spatial and temporal gene expression of four related tetraspanins during the embryonic development of Xenopus laevis by quantitative real-time PCR and in situ hybridization: Tspan3 (encoded by the gene Tm4sf8 gene) Tspan4 (encoded by the gene Tm4sf7), Tspan5 (encoded by the gene Tm4sf9) and Tspan7 (encoded by the gene Tm4sf2). These genes appeared first in the vertebrates during the evolution and are conserved across different species. In humans, they were associated with several diseases such as sclerosis, mental retardation and cancer; however their physiological role remained unclear. This work provides a comprehensive comparative analysis of the expression of these tetraspanins during the development of X. laevis. The more closely related tetraspanins Tspan3, Tspan4 and Tspan7 exhibited very similar spatial expression patterns, albeit differing in their temporal occurrence. The corresponding transcripts were found in the dorsal animal ectoderm at blastula stage. At early tailbud stages (stage 26) the genes were expressed in the migrating cranial neural crest located in the somites, developing eye, brain, and in otic vesicles. In contrast, Tspan5 appeared first at later stages of development and was detected prominently in the notochord. These data support close relatedness of Tspan3, Tspan4 and Tspan7. The expression of these tetraspanins in the cells with a high migratory potential, e.g. neural crest cells, suggests their role in the regulation of migration processes, characteristic for tetraspanin family members, during development. Similarity of the expression profiles might indicate at least partial functional redundancy, which is in concordance with earlier findings of tissue-limited or absent phenotypes in the knock-down studies of tetraspanins family members performed.
四跨膜蛋白构成了一个大家族的整合膜蛋白，参与细胞黏附、迁移和融合的调控。在人类中，它由33个成员组成，分为四个亚家族。在这里，我们通过定量实时PCR和原位杂交技术，研究了非洲爪蟾胚胎发育过程中四种相关四跨膜蛋白的时空基因表达：Tspan3（由Tm4sf8基因编码）、Tspan4（由Tm4sf7基因编码）、Tspan5（由Tm4sf9基因编码）和Tspan7（由Tm4sf2基因编码）。这些基因在进化过程中最早出现在脊椎动物中，并且在不同物种间保守。在人类中，它们与多种疾病相关，如硬化症、智力发育迟缓及癌症；然而它们的生理作用仍不清楚。这项工作对这些四跨膜蛋白在非洲爪蟾发育过程中的表达进行了全面的比较分析。关系更为密切的四跨膜蛋白Tspan3、Tspan4和Tspan7表现出非常相似的空间表达模式，尽管它们出现的时间不同。在囊胚期，相应的转录本在背侧动物外胚层中被发现。在早期尾芽阶段（第26阶段），这些基因在位于体节中的迁移性颅神经嵴、发育中的眼睛、大脑以及耳囊中表达。相比之下，Tspan5最早出现在发育后期，并且在脊索中大量表达。这些数据支持了Tspan3、Tspan4和Tspan7的密切相关性。这些四跨膜蛋白在具有高迁移潜力的细胞（如神经嵴细胞）中的表达，表明它们在发育过程中对迁移过程的调控作用，这是四跨膜蛋白家族成员的特征。表达谱的相似性可能表明至少部分功能冗余，这与之前对四跨膜蛋白家族成员进行敲低研究中组织受限或无表型的早期发现一致。
