The spike of S phase cyclin Cig2 expression at the G1-S border in fission yeast requires both APC and SCF ubiquitin ligases.
We describe a novel set of oscillation mechanisms for the fission yeast S phase cyclin Cig2, which contains an authentic destruction box and is destroyed at anaphase via the APC/cyclosome (APC/C). Unlike the mitotic cyclin Cdc13, however, Cig2 mRNA and protein peak at the G1/S boundary and decline to low levels in G2 and M phases. We show here that SCF(Pop1, Pop2) plays a role in transcriptional periodicity, as pop mutations result in constitutive cig2(+) transcripts. The instability of Cig2 during G2 and M is independent of either the APC/C or Pop1/Pop2, but requires Skp1, a core component of SCF. These data indicate that the APC/C and SCF control Cig2 levels differentially at different stages of the cell cycle.
Yamano
H
H
Laboratory of Cell Cycle Control, Imperial Cancer Research Fund, South Mimms, Herts EN6 3LD, United Kingdom.
Kitamura
K
K
Kominami
K
K
Lehmann
A
A
Katayama
S
S
Hunt
T
T
Toda
T
T
D000705:Anaphase; D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism; D018797:Cell Cycle Proteins; D019926:Cyclin B / Q000378:metabolism; D016213:Cyclins / Q000235:genetics / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D016193:G1 Phase; D016195:G2 Phase; D015966:Gene Expression Regulation, Fungal; D006207:Half-Life; D008025:Ligases / Q000378:metabolism*; D008938:Mitosis; D009097:Multienzyme Complexes / Q000378:metabolism; D009154:Mutation; D010453:Peptide Synthases / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012260:Ribonucleases; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D016196:S Phase; D044843:SKP Cullin F-Box Protein Ligases; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases; D014981:Xenopus
D018797:Cell Cycle Proteins; C080328:Cig2 protein, S pombe; D019926:Cyclin B; D016213:Cyclins; D005656:Fungal Proteins; D009097:Multienzyme Complexes; D012333:RNA, Messenger; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; C490348:pop1 protein, S pombe; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D044843:SKP Cullin F-Box Protein Ligases; D044767:Ubiquitin-Protein Ligases; D016203:CDC2 Protein Kinase; D012260:Ribonucleases; C079009:POP2 protein, S cerevisiae; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D008025:Ligases; D010453:Peptide Synthases