The multidomain structure of Orc1p reveals similarity to regulators of DNA replication and transcriptional silencing.
The origin recognition complex (ORC) is a six protein assembly that binds S. cerevisiae origins of replication and directs DNA replication throughout the genome and transcriptional silencing at the yeast mating-type loci. Here we report the cloning of the genes encoding the 120 kDa (ORC1), 62 kDa (ORC3), and 56 kDa (ORC4) subunits of ORC and the reconstitution of the complete complex after expression of all six subunits in insect cells. Orc1p is related to Cdc6p and Cdc18p, which regulate DNA replication and mitosis, and to Sir3p, a regulator of transcriptional silencing. The N-terminal region of Orc1p is highly related to Sir3p, and studies of Orc1p/Sir3p chimeric proteins indicate that this domain is dedicated to the transcriptional silencing function of ORC.
Bell
S P
SP
Cold Spring Harbor Laboratory, New York 11724, USA.
Mitchell
J
J
Leber
J
J
Kobayashi
R
R
Stillman
B
B
D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000235:genetics; D004261:DNA Replication / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification / Q000648:ultrastructure*; D005656:Fungal Proteins / Q000235:genetics; D005800:Genes, Fungal / Q000235:genetics; D049770:Genes, Mating Type, Fungal; D008969:Molecular Sequence Data; D051738:Origin Recognition Complex; D012326:RNA Splicing / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000302:isolation & purification / Q000648:ultrastructure*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D014158:Transcription, Genetic / Q000235:genetics*
C066503:CDC6 protein, S cerevisiae; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C497214:ORC1 protein, S cerevisiae; C497217:ORC3 protein, S cerevisiae; C497219:ORC4 protein, S cerevisiae; D051738:Origin Recognition Complex; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C082462:cdc18 protein, S pombe