STAG3 is the meiotic component of cohesin and a member of the Cancer Testis Antigen (CTA) family. This gene has been found to be overexpressed in many types of cancer, and recently, its variants have been implicated in other disorders and many human diseases. Therefore, this study aimed to analyze the major variants of STAG3. Western blot (WB) and immunoprecipitation (IP) assays were performed using two different anti-STAG3 antibodies that targeted the relevant protein in MCF-7, T-47D, MDA-MB-468, and MDA-MB-231 breast cancer cells with Jurkat and MCF-10A cells as positive and negative controls, respectively. In silico analyses were searched to study the major isoforms. WB and IP assays revealed two abundant polypeptides < 191 kDa and ~ 75 kDa in size. Specific bioinformatics tools successfully determined the three-dimensional (3-D) structure, the subcellular localization, and the secondary structures of the isoforms. Furthermore, some of the physicochemical properties of the STAG3 proteins were also determined. The results of this study revealed the power of applying the biological techniques (WB and IP) with the bioinformatics assays and the possibility of their exploitation in understanding diseased genes. Exploring the major variants of STAG3 at the protein level could help decipher some disorders associated with their occurrence, along with designing drugs effective at least for some relevant diseases.

中文翻译：

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使用一些蛋白质组学和生物信息学分析表征主要的人类 STAG3 变体

STAG3 是 cohesin 的减数分裂成分，是癌症睾丸抗原 (CTA) 家族的成员。已发现该基因在许多类型的癌症中过度表达，最近，其变体与其他疾病和许多人类疾病有关。因此，本研究旨在分析STAG3的主要变体。使用两种不同的抗 STAG3 抗体进行蛋白质印迹 (WB) 和免疫沉淀 (IP) 检测，这些抗体靶向 MCF-7、T-47D、MDA-MB-468 和 MDA-MB-231 乳腺癌细胞中的相关蛋白质Jurkat 和 MCF-10A 细胞分别作为阳性和阴性对照。搜索了计算机分析以研究主要同种型。WB 和 IP 测定显示两种丰富的多肽 < 191 kDa 和 ~ 75 kDa 的大小。特定的生物信息学工具成功确定了三维（3-D）结构，亚细胞定位和亚型的二级结构。此外，还确定了 STAG3 蛋白的一些理化特性。这项研究的结果揭示了将生物技术（WB 和 IP）与生物信息学分析相结合的力量，以及利用它们来了解患病基因的可能性。在蛋白质水平探索 STAG3 的主要变体可以帮助破译与其发生相关的一些疾病，同时设计至少对某些相关疾病有效的药物。这项研究的结果揭示了将生物技术（WB 和 IP）与生物信息学分析相结合的力量，以及利用它们来了解患病基因的可能性。在蛋白质水平探索 STAG3 的主要变体可以帮助破译与其发生相关的一些疾病，同时设计至少对某些相关疾病有效的药物。这项研究的结果揭示了将生物技术（WB 和 IP）与生物信息学分析相结合的力量，以及利用它们来了解患病基因的可能性。在蛋白质水平探索 STAG3 的主要变体可以帮助破译与其发生相关的一些疾病，同时设计至少对某些相关疾病有效的药物。