Divergent functions of multiple eukaryote-like Orc1/Cdc6 proteins on modulating the loading of the MCM helicase onto the origins of the hyperthermophilic archaeon Sulfolobus solfataricus P2.
The Cdc6 protein has been suggested as a loader for the eukaryotic MCM helicase. Archaeal replication machinery represents a core version of that in eukaryotes. In the current work, three eukaryotic Orc1/Cdc6 homologs (SsoCdc6-1, -2, and -3) from crenarchaeon Sulfolobus solfataricus were shown to have totally different effects on the interactions with SsoMCM helicase. SsoCdc6-2 stimulates the binding of the SsoMCM onto the origin DNA, but SsoCdc6-1 and SsoCdc6-3 significantly inhibit the loading activities, and these inhibitive effects can not be reversed by the stimulation of SsoCdc6-2. Using pull-down assays, we showed that three SsoCdc6 proteins interacted physically with the SsoMCM. Furthermore, the C-terminal domains of SsoCdc6 proteins were shown to physically and functionally affect the interactions with SsoMCM. This is the first report on the divergent functions of multiple eukaryote-like Orc1/Cdc6 proteins on regulating the loading of the MCM helicase onto the origins in the archaeon.
National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Pei-Xia
PX
Jiang
Jun
J
Wang
Ying
Y
Feng
Zheng-Guo
ZG
He
D019843:Archaeal Proteins / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004265:DNA Helicases / Q000378:metabolism*; D004261:DNA Replication; D008957:Models, Genetic; D008969:Molecular Sequence Data; D051738:Origin Recognition Complex / Q000378:metabolism*; D018741:Replication Origin; D048229:Sulfolobus solfataricus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
D019843:Archaeal Proteins; D018797:Cell Cycle Proteins; D051738:Origin Recognition Complex; D004247:DNA; D004265:DNA Helicases