Kumar P Pavan, Franklin Sarah, Emechebe Uchenna, Hu Hao, Moore Barry, Lehman Chris, Yandell Mark, Moon Anne M
Department of Pediatrics, University of Utah, Salt Lake City, Utah, United States of America.
Department of Internal Medicine and the Nora Eccles Harrison Cardiovascular Research & Training Institute, University of Utah, Salt Lake City, Utah, United States of America; Department of Anesthesiology, University of California Los Angeles, Los Angeles, California, United States of America.
PLoS Genet. 2014 Mar 27;10(3):e1004247. doi: 10.1371/journal.pgen.1004247. eCollection 2014 Mar.
TBX3 is a member of the T-box family of transcription factors with critical roles in development, oncogenesis, cell fate, and tissue homeostasis. TBX3 mutations in humans cause complex congenital malformations and Ulnar-mammary syndrome. Previous investigations into TBX3 function focused on its activity as a transcriptional repressor. We used an unbiased proteomic approach to identify TBX3 interacting proteins in vivo and discovered that TBX3 interacts with multiple mRNA splicing factors and RNA metabolic proteins. We discovered that TBX3 regulates alternative splicing in vivo and can promote or inhibit splicing depending on context and transcript. TBX3 associates with alternatively spliced mRNAs and binds RNA directly. TBX3 binds RNAs containing TBX binding motifs, and these motifs are required for regulation of splicing. Our study reveals that TBX3 mutations seen in humans with UMS disrupt its splicing regulatory function. The pleiotropic effects of TBX3 mutations in humans and mice likely result from disrupting at least two molecular functions of this protein: transcriptional regulation and pre-mRNA splicing.
TBX3是T-box转录因子家族的成员，在发育、肿瘤发生、细胞命运和组织稳态中发挥关键作用。人类的TBX3突变会导致复杂的先天性畸形和尺骨-乳腺综合征。先前对TBX3功能的研究集中在其作为转录抑制因子的活性上。我们采用无偏向蛋白质组学方法在体内鉴定与TBX3相互作用的蛋白质，发现TBX3与多种mRNA剪接因子和RNA代谢蛋白相互作用。我们发现TBX3在体内调节可变剪接，并且根据情况和转录本可以促进或抑制剪接。TBX3与可变剪接的mRNA相关联并直接结合RNA。TBX3结合含有TBX结合基序的RNA，这些基序是剪接调控所必需的。我们的研究表明，在患有尺骨-乳腺综合征的人类中发现的TBX3突变会破坏其剪接调节功能。人类和小鼠中TBX3突变的多效性效应可能是由于破坏了该蛋白的至少两种分子功能：转录调控和前体mRNA剪接。
