Department of Chemistry and Biochemistry, Kennesaw State University, Kennesaw, GA 30144, USA.
Int J Mol Sci. 2020 Oct 26;21(21):7929. doi: 10.3390/ijms21217929.
Transcription factors (TFs) have been extensively researched in certain well-studied organisms, but far less so in others. Following the whole-genome sequencing of a new organism, TFs are typically identified through their homology with related proteins in other organisms. However, recent findings demonstrate that structurally similar TFs from distantly related bacteria are not usually evolutionary orthologs. Here we explore TTHB099, a cAMP receptor protein (CRP)-family TF from the extremophile HB8. Using the in vitro iterative selection method Restriction Endonuclease Protection, Selection and Amplification (REPSA), we identified the preferred DNA-binding motif for TTHB099, 5'-TGT(A/g)NBSYRSVN(T/c)ACA-3', and mapped potential binding sites and regulated genes within the HB8 genome. Comparisons with expression profile data in TTHB099-deficient and wild type strains suggested that, unlike CRP (CRP), TTHB099 does not have a simple regulatory mechanism. However, we hypothesize that TTHB099 can be a dual-regulator similar to CRP.
转录因子（TFs）在某些研究充分的生物中得到了广泛研究，但在其他生物中则研究较少。在对新生物进行全基因组测序后，通常通过与其他生物中相关蛋白质的同源性来鉴定 TFs。然而，最近的研究结果表明，来自远缘细菌的结构相似的 TF 通常不是进化上的直系同源物。在这里，我们研究了来自极端微生物 HB8 的 cAMP 受体蛋白（CRP）家族 TF TTHB099。我们使用体外迭代选择方法限制内切酶保护、选择和扩增（REPSA），确定了 TTHB099 的首选 DNA 结合基序，为 5'-TGT(A/g)NBSYRSVN(T/c)ACA-3'，并在 HB8 基因组内绘制了潜在的结合位点和受调控的基因。与 TTHB099 缺失和野生型菌株中的表达谱数据进行比较表明，与 CRP（CRP）不同，TTHB099 没有简单的调节机制。然而，我们假设 TTHB099 可以像 CRP 一样成为双调控因子。
