Petranovic Dina, Michelsen Ole, Zahradka Ksenija, Silva Catarina, Petranovic Mirjana, Jensen Peter Ruhdal, Mijakovic Ivan
Center for Microbial Biotechnology, BioCentrum, Technical University of Denmark, DK-2800 Lyngby, Denmark.
Mol Microbiol. 2007 Mar;63(6):1797-805. doi: 10.1111/j.1365-2958.2007.05625.x.
Bacillus subtilis has recently come into the focus of research on bacterial protein-tyrosine phosphorylation, with several proteins kinases, phosphatases and their substrates identified in this Gram-positive model organism. B. subtilis protein-tyrosine phosphorylation system PtkA/PtpZ was previously shown to regulate the phosphorylation state of UDP-glucose dehydrogenases and single-stranded DNA-binding proteins. This promiscuity towards substrates is reminiscent of eukaryal kinases and has prompted us to investigate possible physiological effects of ptkA and ptpZ gene inactivations in this study. We were unable to identify any striking phenotypes related to control of UDP-glucose dehydrogenases, natural competence and DNA lesion repair; however, a very strong phenotype of DeltaptkA emerged with respect to DNA replication and cell cycle control, as revealed by flow cytometry and fluorescent microscopy. B. subtilis cells lacking the kinase PtkA accumulated extra chromosome equivalents, exhibited aberrant initiation mass for DNA replication and an unusually long D period.
枯草芽孢杆菌最近成为细菌蛋白酪氨酸磷酸化研究的焦点，在这种革兰氏阳性模式生物中已鉴定出几种蛋白激酶、磷酸酶及其底物。先前已证明枯草芽孢杆菌蛋白酪氨酸磷酸化系统PtkA/PtpZ可调节UDP-葡萄糖脱氢酶和单链DNA结合蛋白的磷酸化状态。这种对底物的混杂性让人联想到真核激酶，并促使我们在本研究中探究ptkA和ptpZ基因失活可能产生的生理效应。我们未能鉴定出与UDP-葡萄糖脱氢酶控制、自然感受态和DNA损伤修复相关的任何显著表型；然而，通过流式细胞术和荧光显微镜观察发现，缺失激酶PtkA的枯草芽孢杆菌细胞在DNA复制和细胞周期控制方面出现了非常强烈的表型。缺乏激酶PtkA的枯草芽孢杆菌细胞积累了额外的染色体当量，表现出异常的DNA复制起始质量和异常长的D期。
