Modulation of host cell cycle by viral cyclin-like protein

Cell cycle transitions are driven by activities of cyclin/cyclin-dependent kinase (Cdk) complexes. Cyclins are a diverse family of proteins containing a conserved region concentrated in a 100 amino acid stretch, known as the “cyclin box” which is necessary for Cdk binding and activation. They are grouped according to the cell cycle phase they regulate. Cyclin D family members are G1 phase cyclins. Cyclin E and Cyclin A are able to bind Cdk2 and promote the cell cycle progression through G1/S transition. Cyclins B are M-phase cyclins.

cycB cycB cycD cycE cycA cdk1 cdk1 cdk4 cdk2 cdk2 cdk6 cdk3 cdk6 rb rb EC27 vcyc rcyc rcyc Image Map

Originally found in several herpesviruses genomes, viral encoded cyclins have been identified in several viral families including retroviruses. Some viral cyclins are able to induce hyperproliferation in infected hosts, which sometimes lead to malignancies. Many viral cyclins are homolog to cellular cyclin D, which regulates the G1 phase. The MHV-68 encoded cyclin is equally related to cyclin D, A and E. The functions attributed to viral cyclins correspond to cellular cyclins by inducing the G1/S phase transition, by hyperphosphorylating host RB or inducing host p27Kip1 degradation. Instead, the ODV-EC27 from baculovirus shares similarities with cyclin B, binds CDK1, thus prevents the binding of cyclin B to CDK1. In turn, the cell arrests in G2/M.

Matching UniProtKB/Swiss-Prot entries

4 entries grouped by strain (browse by keywords)

1 entry

Autographa californica nuclear polyhedrosis virus (AcMNPV) reference strain

E27_NPVAC Occlusion-derived virus envelope protein E27 (ODV-E27)

1 entry

Orgyia pseudotsugata multicapsid polyhedrosis virus (OpMNPV) reference strain

OE27_NPVOP Occlusion-derived virus envelope protein E27 (ODV-E27)

1 entry

Saimiriine herpesvirus 2 (strain 11) (SaHV-2) (Herpesvirus saimiri) reference strain

CGH2_SHV21 Cyclin homolog (V-cyclin)

1 entry

Walleye dermal sarcoma virus (WDSV) reference strain

CYCL_WDSV Retroviral cyclin (Rv-cyclin) (ORF-A protein)