Di Pietro Cinzia, Ragusa Marco, Duro Laura, Guglielmino Maria Rosa, Barbagallo Davide, Carnemolla Alisia, Laganà Alessandro, Buffa Pietro, Angelica Rosario, Rinaldi Antonella, Calafato Maria Stella, Milicia Ionella, Caserta Cinzia, Giugno Rosalba, Pulvirenti Alfredo, Giunta Veronica, Rapisarda Antonella, Di Pietro Valentina, Grillo Agata, Messina Angelo, Ferro Alfredo, Grzeschik Karl Heinz, Purrello Michele
Dipartimento di Scienze Biomediche-Unità di Biologia Genetica e BioInformatica, Università di Catania, Catania, Italy, EU.
DNA Cell Biol. 2007 Jun;26(6):369-85. doi: 10.1089/dna.2006.0527.
TBPL2 is the most recently discovered and less characterized member of the TATA box binding protein (TBP) family that also comprises TBP, TATA box binding protein-like 1 (TBPL1), and Drosophila melanogaster TBP related factor (TRF). In this paper we report our in silico and in vitro data on (i) the genomics of the TBPL2 gene in Homo sapiens, Pan troglodytes, Mus musculus, Rattus norvegicus, Gallus gallus, Xenopus tropicalis, and Takifugu rubripes; (ii) its evolution and phylogenetic relationship with TBP, TBPL1, and TRF; (iii) the structure of the TBPL2 proteins that belong to the recently identified group of the intrinsically unstructured proteins (IUPs); and (iv) TBPL2 expression in different organs and cell types of Homo sapiens and Rattus norvegicus. Similar to TBP, both the TBPL2 gene and protein are bimodular. The 3' region of the gene encoding the DNA binding domain (DBD) was well conserved during evolution. Its high homology to vertebrate TBP suggests that TBPL2 also should bind to the TATA box and interact with the proteins binding to TBP carboxy-terminal domain, such as the TBP associated factors (TAFs). As already demonstrated for TBP, TBPL2 amino-terminal segment is intrinsically unstructured and, even though variable among vertebrates, comprises a highly conserved motif not found in any other known protein. Absence of TBPL2 from the genome of invertebrates and plants demonstrates its specific origin within the subphylum of vertebrates. Our RT-PCR analysis of human and rat RNA shows that, similar to TBP, TBPL2 is ubiquitously synthesized even though at variable levels that are at least two orders of magnitude lower. Higher expression of TBPL2 in the gonads than in other organs suggests that it could perform important functions in gametogenesis. Our genomic and expression data should contribute to clarify why TBP has a general master role within the transcription apparatus (TA), whereas both TBPL1 and TBPL2 perform tissue-specific functions.
TBPL2是TATA框结合蛋白（TBP）家族中最近发现且特征描述较少的成员，该家族还包括TBP、TATA框结合蛋白样1（TBPL1）和黑腹果蝇TBP相关因子（TRF）。在本文中，我们报告了关于以下方面的计算机模拟和体外实验数据：（i）人类、黑猩猩、小鼠、大鼠、鸡、热带爪蟾和红鳍东方鲀中TBPL2基因的基因组学；（ii）其与TBP、TBPL1和TRF的进化及系统发育关系；（iii）属于最近鉴定出的内在无序蛋白（IUPs）组的TBPL2蛋白的结构；（iv）TBPL2在人类和大鼠不同器官及细胞类型中的表达。与TBP相似，TBPL2基因和蛋白均为双模块。编码DNA结合结构域（DBD）的基因3'区域在进化过程中高度保守。它与脊椎动物TBP的高度同源性表明，TBPL2也应与TATA框结合，并与结合到TBP羧基末端结构域的蛋白相互作用，如TBP相关因子（TAFs）。正如已在TBP中证明的那样，TBPL2氨基末端片段本质上是无序的，尽管在脊椎动物中存在差异，但包含一个在任何其他已知蛋白中都未发现的高度保守基序。无脊椎动物和植物基因组中不存在TBPL2，这表明它在脊椎动物亚门内具有特定起源。我们对人类和大鼠RNA的RT-PCR分析表明，与TBP相似，TBPL2在各处均有合成，尽管其水平变化很大，至少低两个数量级。TBPL2在性腺中的表达高于其他器官，这表明它可能在配子发生中发挥重要作用。我们的基因组和表达数据应有助于阐明为什么TBP在转录装置（TA）中具有普遍的主导作用，而TBPL1和TBPL2都执行组织特异性功能。
