Ishqi Hassan Mubarak, Husain Mohammed Amir, Rehman Sayeed Ur, Sarwar Tarique, Tabish Mohammad
Department of Biochemistry, Faculty of Life Sciences, A.M. University, Aligarh, U.P., 202002, India.
Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India.
Mol Biol Rep. 2018 Oct;45(5):699-711. doi: 10.1007/s11033-018-4209-5. Epub 2018 Jun 14.
MYD88 is an adaptor protein known to involve in activation of NF-κB through IL-1 receptor and TLR stimulation. It consists of N-terminal death domain and C-terminal Toll/IL-R homology domain that mediates its interaction with IL-1R associated kinase and IL-1R/TLR, respectively. MYD88 contributes to various types of carcinogenesis due to its involvement in oncogene induced inflammation. In the present study, we have recognized two new alternatively spliced variants of MyD88 gene in mouse using bioinformatics tools and molecular biology techniques in combination. The newly identified non-coding exon (NE-1) from 5' upstream region alternatively splices with either exon E-2 or exon E-5 to produce two novel transcript variants MyD88N1 and MyD88N2 respectively. The transcript variant MyD88N1 was expressed in several tissues studied while the variant MyD88N2 was found to be expressed only in the brain. The analysis of the upstream region of novel exon by in silico approach revealed new promoter region PN, which possess potential signature sequences for diverse transcription factors, suggesting complex gene regulation. Studies of post translational modifications of conceptualized amino acid sequences of these isoforms revealed diversity in properties. Western blot analysis further confirmed the expression of protein isoform MYD88N1.
髓样分化因子88（MYD88）是一种衔接蛋白，已知其通过白细胞介素-1受体（IL-1受体）和Toll样受体（TLR）刺激参与核因子κB（NF-κB）的激活。它由N端死亡结构域和C端Toll/白细胞介素-1受体（IL-R）同源结构域组成，分别介导其与IL-1受体相关激酶以及IL-1受体/TLR的相互作用。由于MYD88参与致癌基因诱导的炎症反应，它在多种类型的肿瘤发生过程中发挥作用。在本研究中，我们结合生物信息学工具和分子生物学技术，在小鼠中识别出了髓样分化因子88（MyD88）基因的两种新的可变剪接变体。新鉴定出的位于5'上游区域的非编码外显子（NE-1）与外显子E-2或外显子E-5可变剪接，分别产生两种新的转录变体MyD88N1和MyD88N2。转录变体MyD88N1在所研究的几种组织中均有表达，而变体MyD88N2仅在脑中表达。通过计算机分析方法对新外显子上游区域进行分析，发现了新的启动子区域PN，该区域具有多种转录因子的潜在特征序列，提示存在复杂的基因调控。对这些异构体概念化氨基酸序列的翻译后修饰研究揭示了其性质的多样性。蛋白质免疫印迹分析进一步证实了蛋白异构体MYD88N1的表达。
