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.
Jiang
Pei-Xia
PX
National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Wang
Jun
J
Feng
Ying
Y
He
Zheng-Guo
ZG
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