Zavec Apolonija Bedina, Comino Aleksandra, Lenassi Metka, Komel Radovan
Laboratory for Biosynthesis and Biotransformation, National Institute of Chemistry, Hajdrihova, Ljubljana, Slovenia.
FEMS Yeast Res. 2008 Feb;8(1):64-70. doi: 10.1111/j.1567-1364.2007.00307.x. Epub 2007 Sep 19.
Damaged regulation of the small ubiquitin-like modifier (SUMO) system contributes to some human diseases; therefore, it is very important to identify the SUMO targets and to determine the function of their sumoylation. In this study, it is shown that Ecm11 protein in Saccharomyces cerevisiae is modified by SUMO during meiosis. It is known that Ecm11 is required in the early stages of yeast meiosis where its function is related to DNA replication and crossing over. Here it is shown that the level of Ecm11 protein is low in mitosis, but high in meiosis. The highest level of Ecm11 is in the early-middle phase of sporulation. A specific site of sumoylation was identified in Ecm11 at Lys5 and evidence is provided that sumoylation at this site directly regulates Ecm11 function in meiosis. On the other hand, no relationship was observed between sumoylation of Ecm11 and its role during vegetative growth. It was shown that Ecm11 interacts with Siz2 SUMO ligase in a two-hybrid system; although Siz2 is not essential for the Ecm11 sumoylation.
小泛素样修饰物(SUMO)系统的调控受损会导致一些人类疾病;因此,识别SUMO靶点并确定其SUMO化修饰的功能非常重要。在本研究中,结果表明酿酒酵母中的Ecm11蛋白在减数分裂过程中会被SUMO修饰。已知Ecm11在酵母减数分裂的早期阶段是必需的,其功能与DNA复制和交叉互换有关。在此研究中表明,Ecm11蛋白在有丝分裂时水平较低,但在减数分裂时水平较高。Ecm11的最高水平出现在孢子形成的中前期。在Ecm11的赖氨酸5位点鉴定出一个特定的SUMO化修饰位点,并且有证据表明该位点的SUMO化修饰直接调控Ecm11在减数分裂中的功能。另一方面,未观察到Ecm11的SUMO化修饰与其在营养生长过程中的作用之间存在关联。研究表明,在双杂交系统中Ecm11与Siz2 SUMO连接酶相互作用;尽管Siz2对于Ecm11的SUMO化修饰并非必需。