College of Medical Laboratory Science, Guilin Medical University, Guilin, Guangxi 541004, China.
Guihang Guiyang Hospital Affiliated to Zunyi Medical University, Guiyang, Guizhou 550027, China.
Aging (Albany NY). 2022 Sep 12;14(17):7126-7136. doi: 10.18632/aging.204285.
Zbtb34 is a novel zinc finger protein, which is revealed by biological software analysis to have 3 zinc fingers, but its functions remain unknown. In this study, mouse cDNA was amplified by PCR and inserted into the plasmid pEGFP-N1 to generate Zbtb34-EGFP fusion protein. The upregulation of Zbtb34 in mouse embryonic stem cells promoted telomere elongation and increased cell proliferation. In order to understand the above phenomena, the telomere co-immunoprecipitation technique was employed to investigate the relationship between Zbtb34 and telomeres. The results indicated that Zbtb34 could bind to the DNA sequences of the telomeres. Alanine substitution of the third zinc finger abolished such binding. Since Pot1 is the only protein binding to the single-stranded DNA at the end of the telomeres, we further investigated the relationship between Zbtb34 and Pot1. The results revealed that the upregulation of Zbtb34 decreased the binding of Pot1b to the telomeres. Through the upregulation of Pot1b, the binding of Zbtb34 to the telomeres was also reduced. In conclusion, we showed that the main biological function of Zbtb34 was to bind telomere DNA via its third ZnF, competing with Pot1b for the binding sites, resulting in telomere elongation and cell proliferation.
Zbtb34 是一种新型锌指蛋白，通过生物软件分析发现其具有 3 个锌指，但功能未知。本研究通过 PCR 扩增小鼠 cDNA，插入质粒 pEGFP-N1 中生成 Zbtb34-EGFP 融合蛋白。在小鼠胚胎干细胞中上调 Zbtb34 可促进端粒延长并增加细胞增殖。为了了解上述现象，采用端粒共免疫沉淀技术研究 Zbtb34 与端粒的关系。结果表明，Zbtb34 可与端粒的 DNA 序列结合。第三个锌指的丙氨酸取代会破坏这种结合。由于 Pot1 是唯一与端粒末端的单链 DNA 结合的蛋白，我们进一步研究了 Zbtb34 与 Pot1 之间的关系。结果表明，上调 Zbtb34 会降低 Pot1b 与端粒的结合。通过上调 Pot1b，Zbtb34 与端粒的结合也减少了。综上所述，我们表明 Zbtb34 的主要生物学功能是通过其第三个 ZnF 结合端粒 DNA，与 Pot1b 竞争结合位点，导致端粒延长和细胞增殖。
