title: Protein kinase A is required for chromosomal DNA replication.
abstract: Passage through mitosis resets cells for a new round of chromosomal DNA replication [1]. In late mitosis, the pre-replication complex - which includes the origin recognition complex (ORC), Cdc6 and the minichromosome maintenance (MCM) proteins - binds chromatin as a pre-requisite for DNA replication. S-phase-promoting cyclin-dependent kinases (Cdks) and the kinase Dbf4-Cdc7 then act to initiate replication. Before the onset of replication Cdc6 dissociates from chromatin. S-phase and M-phase Cdks block the formation of a new pre-replication complex, preventing DNA over-replication during the S, G2 and M phases of the cell cycle [1]. The nuclear membrane also contributes to limit genome replication to once per cell cycle [2]. Thus, at the end of M phase, nuclear membrane breakdown and the collapse of Cdk activity reset cells for a new round of chromosomal replication. We showed previously that protein kinase A (PKA) activity oscillates during the cell cycle in Xenopus egg extracts, peaking in late mitosis. The oscillations are induced by the M-phase-promoting Cdk [3] [4]. Here, we found that PKA oscillation was required for the following phase of DNA replication. PKA activity was needed from mitosis exit to the formation of the nuclear envelope. PKA was not required for the assembly of ORC2, Cdc6 and MCM3 onto chromatin. Inhibition of PKA activity, however, blocked the release of Cdc6 from chromatin and subsequent DNA replication. These data suggest that PKA activation in late M phase is required for the following S phase.
authors.affiliation: Dipartimento di Biologia e Patologia Molecolare e Cellulare "L. Califano", c/o Centro di Endocrinologia ed Oncologia Sperimentale del CNR, II Medical School, University of Naples, Via S. Pansini 5, Naples, 80131, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Costanzo
authors.forename: E V
authors.initials: EV
authors.lastname: Avvedimento
authors.forename: M E
authors.initials: ME
authors.lastname: Gottesman
authors.forename: J
authors.initials: J
authors.lastname: Gautier
authors.forename: D
authors.initials: D
authors.lastname: Grieco
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics; D002843:Chromatin / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D004261:DNA Replication / Q000187:drug effects / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D003720:Densitometry; D004789:Enzyme Activation; D005982:Glutathione Transferase / Q000494:pharmacology; D015151:Immunoblotting; D008297:Male; D008938:Mitosis / Q000187:drug effects; D051738:Origin Recognition Complex; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D029701:Saccharomyces cerevisiae Proteins; D013094:Spermatozoa / Q000502:physiology; D014981:Xenopus / Q000235:genetics / Q000254:growth & development
chemical_list: C066503:CDC6 protein, S cerevisiae; D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; D051738:Origin Recognition Complex; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D015124:8-Bromo Cyclic Adenosine Monophosphate; D005982:Glutathione Transferase; D017868:Cyclic AMP-Dependent Protein Kinases