We have previously found and characterized two pairs of enhancer elements, E1 and E2, in the type II collagen alpha 1 chain (COL2A1) gene. Subsequent studies have suggested that these enhancers function differently in the regulation of gene expression. For example, histone deacetylase 10 modifies only the E2 enhancer region to affect gene expression. Therefore, in this study, we aimed to clarify the transcriptional complex formed at each enhancer region by identifying transcription factors that specifically bind to each enhancer element. To this end, we used chondrocytic cell lines established using our unique silent reporter system and overexpressed candidate transcription factors in these cells. We found two transcription factors, other than the SOX trio, that directly bound to COL2A1 and regulated its expression. The first was Kruppel-like factor-4 (KLF4), which bound to the promoter proximal region, and the second was AT-rich interactive domain 5B (ARID5B) which bound to the E1 enhancer element. Further studies are needed to identify factors that specifically bind to the E2 enhancer element. In any case, our findings provide an important insight into the molecular mechanisms underlying the regulation of COL2A1. In this paper, we reevaluated the previous analysis of transcription factors involved in the regulation of COL2A1 expression.

我们之前已经发现并鉴定了II型胶原蛋白α1链（COL2A1）基因中的两对增强子E1和E2 。随后的研究表明这些增强子在基因表达的调节中发挥不同的作用。例如，组蛋白脱乙酰基酶10仅修饰E2增强子区域以影响基因表达。因此，在这项研究中，我们旨在通过鉴定与每个增强子元件特异性结合的转录因子来阐明在每个增强子区域形成的转录复合物。为此，我们使用了通过我们独特的沉默报告系统建立的软骨细胞系，并在这些细胞中过度表达了候选转录因子。我们发现除了SOX三重奏以外，还有两个直接与COL2A1结合的转录因子并调节其表达。第一个是与启动子近端区域结合的Kruppel样因子4（KLF4），第二个是与E1增强子元件结合的富含AT的相互作用域5B（ARID5B）。需要进一步的研究来鉴定特异性结合E2增强子的因子。无论如何，我们的发现为深入了解COL2A1调控的分子机制提供了重要的见识。在本文中，我们重新评估了先前涉及调控COL2A1表达的转录因子分析。