title: Recruitment of cyclin-dependent kinase 9 to nuclear compartments during cytomegalovirus late replication: importance of an interaction between viral pUL69 and cyclin T1.
abstract: Cyclin-dependent protein kinases (CDKs) are important regulators of cellular processes and are functionally integrated into the replication of human cytomegalovirus (HCMV). Recently, a regulatory impact of CDK activity on the viral mRNA export factor pUL69 was shown. Here, specific aspects of the mode of interaction between CDK9/cyclin T1 and pUL69 are described. Intracellular localization was studied in the presence of a novel selective CDK9 inhibitor, R22, which exerts anti-cytomegaloviral activity in vitro. A pronounced R22-induced formation of nuclear speckled aggregation of pUL69 was demonstrated. Multi-labelling confocal laser-scanning microscopy revealed that CDK9 and cyclin T1 co-localized perfectly with pUL69 in individual speckles. The effects were similar to those described recently for the broad CDK inhibitor roscovitine. Co-immunoprecipitation and yeast two-hybrid analyses showed that cyclin T1 interacted with both CDK9 and pUL69. The interaction region of pUL69 for cyclin T1 could be attributed to aa 269-487. Moreover, another component of CDK inhibitor-induced speckled aggregates was identified with RNA polymerase II, supporting earlier reports that strongly suggested an association of pUL69 with transcription complexes. Interestingly, when using a UL69-deleted recombinant HCMV, no speckled aggregates were formed by CDK inhibitor treatment. This indicated that pUL69 is the defining component of aggregates and generally may represent a crucial viral interactor of cyclin T1. In conclusion, these data emphasize that HCMV inter-regulation with CDK9/cyclin T1 is at least partly based on a pUL69-cylin T1 interaction, thus contributing to the importance of CDK9 for HCMV replication.
authors: Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors: Sabine
authors: S
authors: Feichtinger
authors: Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors: Thomas
authors: T
authors: Stamminger
authors: Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors: Regina
authors: R
authors: Müller
authors: Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors: Laura
authors: L
authors: Graf
authors: GPC Biotech AG, Martinsried, Germany.
authors: Bert
authors: B
authors: Klebl
authors: GPC Biotech AG, Martinsried, Germany.
authors: Jan
authors: J
authors: Eickhoff
authors: Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors: Manfred
authors: M
authors: Marschall
mesh_terms: D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology* / Q000235:genetics / Q000821:virology; D056906:Cyclin T / Q000235:genetics / Q000378:metabolism*; D042863:Cyclin-Dependent Kinase 9 / Q000235:genetics / Q000378:metabolism*; D003587:Cytomegalovirus / Q000235:genetics / Q000502:physiology*; D003586:Cytomegalovirus Infections / Q000201:enzymology / Q000378:metabolism* / Q000821:virology; D006801:Humans; D011485:Protein Binding; D021381:Protein Transport; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: C503684:CCNT1 protein, human; D056906:Cyclin T; D015534:Trans-Activators; C446019:pUL69 protein, Human herpesvirus 5; D042863:Cyclin-Dependent Kinase 9