title: A B-myb--DREAM complex is not critical to regulate the G2/M genes in HPV-transformed cell lines.
abstract: OBJECTIVE
  It is well-established that HPV E7 proteins, encoded by human papillomavirus (HPV) genes, frequently associated with cervical cancers bind avidly to the retinoblastoma (RB) family of pocket proteins and disrupt their association with members of the E2F transcription factor family. Our previous study showed that the repressive p130-dimerization partner, RB-like, E2F and multi-vulval class (DREAM) complex was disrupted by HPV16 E7 proteins in order to maintain the viral replication in CaSki cells. However, we would like to address whether the activator B-myb-DREAM complex is critical in regulating the replication and mitosis phase since our previous study showed increased B-myb-DREAM expression in HPV-transformed cell lines when compared to control cells.
  
  
  RESULTS
  The association of B-myb with both LIN-54 and LIN-9 was equally decreased by depleting LIN-54 in CaSki cells. Flow cytometry analysis showed that LIN-54 depletion caused an increased proportion of G2/M cells in T98G, SiHa and CaSki cells. The mRNA levels of certain S/G2 genes such as cyclin B, aurora kinase A and Polo-like kinase 1 have demonstrated a marginal increased in CaSki-Lin-54-depleted cells when compared to SiHa- and T98G-Lin-54-depleted cells. We further confirmed this experiment by depleting the B-myb itself in CaSki cells and the results showed the same pattern of cell cycle and mRNA levels for S/G2 genes when compared to LIN-54- and LIN-9-depleted cells.
  
  
  CONCLUSIONS
  The B-myb-DREAM complex might not be vital for progression through mitosis in cells lacking a G1/S checkpoint and not as crucial as the p130-DREAM complex for the survival of the HPV virus.
authors.affiliation: Section of Virology, Department of Medicine, Imperial College London, London, U.K. Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia nurshamimi@um.edu.my.
authors.forename: Nurshamimi Nor
authors.initials: NN
authors.lastname: Rashid
authors.affiliation: Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Rohana
authors.initials: R
authors.lastname: Yusof
authors.affiliation: Section of Virology, Department of Medicine, Imperial College London, London, U.K. Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, U.K.
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Watson
mesh_terms: D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology*; D049109:Cell Proliferation; D002472:Cell Transformation, Viral / Q000235:genetics*; D005260:Female; D005434:Flow Cytometry; D016195:G2 Phase / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic; D018816:Genes, cdc / Q000502:physiology*; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism / Q000821:virology; D052162:Human papillomavirus 16 / Q000472:pathogenicity; D006801:Humans; D047468:Immunoprecipitation; D051605:Kv Channel-Interacting Proteins / Q000235:genetics / Q000378:metabolism*; D050725:Papillomavirus E7 Proteins / Q000378:metabolism; D030361:Papillomavirus Infections / Q000235:genetics / Q000378:metabolism / Q000821:virology; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms / Q000235:genetics / Q000378:metabolism / Q000821:virology
chemical_list: D018797:Cell Cycle Proteins; D051605:Kv Channel-Interacting Proteins; D050725:Papillomavirus E7 Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D015534:Trans-Activators; C496749:KCNIP3 protein, human; C523006:LIN54 protein, human; C064352:MYBL2 protein, human; C059731:oncogene protein E7, Human papillomavirus type 16
keywords: B-myb; DREAM complex; HPV16 E7; Human papillomavirus; p130