Kollati Yedukondalu, Akella Radha Rama Devi, Naushad Shaik Mohammad, Patel Rajesh K, Reddy G Bhanuprakash, Dirisala Vijaya R
Department of Biotechnology, Vignan's University, Vadlamudi, Guntur, Andhra Pradesh 522213, India.
Department of Genetics, Rainbow Children's Hospital, Banjara Hills, Hyderabad, Telangana 500009, India.
Genomics Inform. 2021 Sep;19(3):e29. doi: 10.5808/gi.21034. Epub 2021 Sep 30.
In our previous studies, we have demonstrated the association of certain variants of the thyroid-stimulating hormone receptor (TSHR), thyroid peroxidase (TPO), and thyroglobulin (TG) genes with congenital hypothyroidism. Herein, we explored the mechanistic basis for this association using different in silico tools. The mRNA 3'-untranslated region (3'-UTR) plays key roles in gene expression at the post-transcriptional level. In TSHR variants (rs2268477, rs7144481, and rs17630128), the binding affinity of microRNAs (miRs) (hsa-miR-154-5p, hsa-miR-376a-2-5p, hsa-miR-3935, hsa-miR-4280, and hsa-miR-6858-3p) to the 3'-UTR is disrupted, affecting post-transcriptional gene regulation. TPO and TG are the two key proteins necessary for the biosynthesis of thyroid hormones in the presence of iodide and H2O2. Reduced stability of these proteins leads to aberrant biosynthesis of thyroid hormones. Compared to the wild-type TPO protein, the p.S398T variant was found to exhibit less stability and significant rearrangements of intra-atomic bonds affecting the stoichiometry and substrate binding (binding energies, ΔG of wild-type vs. mutant: ‒15 vs. ‒13.8 kcal/mol; and dissociation constant, Kd of wild-type vs. mutant: 7.2E-12 vs. 7.0E-11 M). The missense mutations p.G653D and p.R1999W on the TG protein showed altered ΔG (0.24 kcal/mol and 0.79 kcal/mol, respectively). In conclusion, an in silico analysis of TSHR genetic variants in the 3'-UTR showed that they alter the binding affinities of different miRs. The TPO protein structure and mutant protein complex (p.S398T) are less stable, with potentially deleterious effects. A structural and energy analysis showed that TG mutations (p.G653D and p.R1999W) reduce the stability of the TG protein and affect its structure-functional relationship.
在我们之前的研究中，我们已经证明促甲状腺激素受体（TSHR）、甲状腺过氧化物酶（TPO）和甲状腺球蛋白（TG）基因的某些变体与先天性甲状腺功能减退症有关。在此，我们使用不同的计算机模拟工具探索了这种关联的机制基础。mRNA 3'-非翻译区（3'-UTR）在转录后水平的基因表达中起关键作用。在TSHR变体（rs2268477、rs7144481和rs17630128）中，微小RNA（miR）（hsa-miR-154-5p、hsa-miR-376a-2-5p、hsa-miR-3935、hsa-miR-4280和hsa-miR-6858-3p）与3'-UTR的结合亲和力被破坏，影响转录后基因调控。TPO和TG是在碘化物和H2O2存在下甲状腺激素生物合成所需的两种关键蛋白质。这些蛋白质稳定性的降低导致甲状腺激素的异常生物合成。与野生型TPO蛋白相比，发现p.S398T变体表现出较低的稳定性以及原子内键的显著重排，影响化学计量和底物结合（野生型与突变体的结合能，ΔG：-15与-13.8 kcal/mol；解离常数，野生型与突变体的Kd：7.2E-12与7.0E-11 M）。TG蛋白上的错义突变p.G65T和p.R1999W显示出改变的ΔG（分别为0.24 kcal/mol和0.79 kcal/mol）。总之，对3'-UTR中TSHR基因变体的计算机模拟分析表明，它们改变了不同miR 的结合亲和力。TPO蛋白结构和突变蛋白复合物（p.S398T）稳定性较低，具有潜在有害影响。结构和能量分析表明，TG突变（p.G653D和p.R1999W）会降低TG蛋白的稳定性并影响其结构-功能关系。
