Jia Shunji, Meng Anming
Protein Science Laboratory of the Ministry of Education, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, China.
Dev Dyn. 2007 Apr;236(4):913-21. doi: 10.1002/dvdy.21092.
Members of the Btg/Tob protein family share a conserved N-terminal region that confers the activity to inhibit cell proliferation. Tob1 and Tob2 proteins, which constitute a Tob subfamily, have a longer C-terminal region than BTG proteins. Apparently, genomes of invertebrates and teleost species contain only a single Tob locus, whereas genomes of mammalian, avian, and amphibian species contain two Tob loci (Tob1 and Tob2). Tob genes are expressed in oocytes, sperm, early embryos, and various adult tissues, depending on the species. Recent reports indicate that Tob proteins play important roles in spermatogenesis, embryonic dorsoventral patterning, osteogenesis, T-cell activation, and learning and memory. Accumulating evidence supports the hypothesis that Tob proteins act primarily as transcriptional repressors in several signaling pathways.
Btg/Tob蛋白家族成员共享一个保守的N端区域，该区域赋予抑制细胞增殖的活性。构成Tob亚家族的Tob1和Tob2蛋白，其C端区域比BTG蛋白更长。显然，无脊椎动物和硬骨鱼物种的基因组仅包含一个Tob基因座，而哺乳动物、鸟类和两栖动物物种的基因组包含两个Tob基因座（Tob1和Tob2）。根据物种不同，Tob基因在卵母细胞、精子、早期胚胎和各种成年组织中表达。最近的报道表明，Tob蛋白在精子发生、胚胎背腹模式形成、骨生成、T细胞活化以及学习和记忆中发挥重要作用。越来越多的证据支持这样的假设，即Tob蛋白在几种信号通路中主要作为转录抑制因子发挥作用。
