Cátedra de Bioquímica y Biología Molecular, Facultad de Ciencias Médicas-INICSA, CONICET-Universidad Nacional de Córdoba, Haya de la Torre s/n, Pabellón Argentina, 2º piso. Ciudad Universitaria, Cordoba CP5000, Argentina.
Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, C/ Zacarías González, nº2, 37007 Salamanca, Spain.
Cells. 2022 Oct 21;11(20):3320. doi: 10.3390/cells11203320.
Sub1 (ScSub1) has been defined as a transcriptional stimulatory protein due to its homology to the ssDNA binding domain (ssDBD) of human PC4 (hPC4). Recently, PC4/Sub1 orthologues have been elucidated in eukaryotes, prokaryotes, and bacteriophages with functions related to DNA metabolism. Additionally, ScSub1 contains a unique carboxyl-terminal region (CT) of unknown function up to date. Specifically, it has been shown that Sub1 is required for transcription activation, as well as other processes, throughout the transcription cycle. Despite the progress that has been made in understanding the mechanism underlying Sub1's functions, some questions remain unanswered. As a case in point: whether Sub1's roles in initiation and elongation are differentially predicated on distinct regions of the protein or how Sub1's functions are regulated. Here, we uncover some residues that are key for DNA-ScSub1 interaction in vivo, localized in the ssDBD, and required for Sub1 recruitment to promoters. Furthermore, using an array of genetic and molecular techniques, we demonstrate that the CT region is required for transcription elongation by RNA polymerase II (RNAPII). Altogether, our data indicate that Sub1 plays a dual role during transcription-in initiation through the ssDBD and in elongation through the CT region.
Sub1（ScSub1）因其与人类 PC4（hPC4）的 ssDNA 结合域（ssDBD）的同源性而被定义为转录激活蛋白。最近，在真核生物、原核生物和噬菌体中已经阐明了与 PC4/Sub1 同源的蛋白，其功能与 DNA 代谢有关。此外，ScSub1 迄今为止还包含一个未知功能的独特羧基末端区域（CT）。具体来说，已经表明 Sub1 是转录激活以及整个转录周期中其他过程所必需的。尽管在理解 Sub1 功能的机制方面已经取得了进展，但仍有一些问题尚未得到解答。例如：Sub1 在起始和延伸中的作用是否基于蛋白质的不同区域，或者 Sub1 的功能如何受到调节。在这里，我们发现了一些在体内与 DNA-ScSub1 相互作用至关重要的残基，这些残基定位于 ssDBD 中，并且对于 Sub1 募集到启动子是必需的。此外，我们使用一系列遗传和分子技术证明 CT 区域对于 RNA 聚合酶 II（RNAPII）的转录延伸是必需的。总之，我们的数据表明 Sub1 在转录过程中发挥双重作用——通过 ssDBD 在起始阶段，通过 CT 区域在延伸阶段。
