Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, 04103, Leipzig, Germany.
Leipzig University Medical Center, IFB Adiposity Diseases, 04103, Leipzig, Germany.
Sci Rep. 2019 Jul 30;9(1):11036. doi: 10.1038/s41598-019-46265-x.
The enormous sizes of adhesion G protein-coupled receptors (aGPCRs) go along with complex genomic exon-intron architectures giving rise to multiple mRNA variants. There is a need for a comprehensive catalog of aGPCR variants for proper evaluation of the complex functions of aGPCRs found in structural, in vitro and animal model studies. We used an established bioinformatics pipeline to extract, quantify and visualize mRNA variants of aGPCRs from deeply sequenced transcriptomes. Data analysis showed that aGPCRs have multiple transcription start sites even within introns and that tissue-specific splicing is frequent. On average, 19 significantly expressed transcript variants are derived from a given aGPCR gene. The domain architecture of the N terminus encoded by transcript variants often differs and N termini without or with an incomplete seven-helix transmembrane anchor as well as separate seven-helix transmembrane domains are frequently derived from aGPCR genes. Experimental analyses of selected aGPCR transcript variants revealed marked functional differences. Our analysis has an impact on a rational design of aGPCR constructs for structural analyses and gene-deficient mouse lines and provides new support for independent functions of both, the large N terminus and the transmembrane domain of aGPCRs.
黏附 G 蛋白偶联受体（aGPCR）的巨大尺寸伴随着复杂的基因组外显子-内含子结构，产生了多种 mRNA 变体。需要对 aGPCR 变体进行全面编目，以便正确评估结构、体外和动物模型研究中发现的 aGPCR 复杂功能。我们使用已建立的生物信息学管道从深度测序的转录组中提取、量化和可视化 aGPCR 的 mRNA 变体。数据分析表明，aGPCR 甚至在内含子中也具有多个转录起始位点，组织特异性剪接很常见。平均而言，给定的 aGPCR 基因可产生 19 种表达显著的转录变体。由转录变体编码的 N 末端的结构域架构通常不同，并且没有或具有不完整的七螺旋跨膜锚以及单独的七螺旋跨膜结构域的 N 末端经常来自 aGPCR 基因。对选定的 aGPCR 转录变体的实验分析显示出明显的功能差异。我们的分析对 aGPCR 结构分析和基因缺失小鼠品系的构建体的合理设计有影响，并为 aGPCR 的大 N 末端和跨膜结构域的独立功能提供了新的支持。
