Retroviral cyclin controls cyclin-dependent kinase 8-mediated transcription elongation and reinitiation
Abstract
Walleye dermal sarcoma virus (WDSV) infection is associated with the seasonal development and regression of walleye dermal sarcoma. Previous work showed that the retroviral cyclin (RV-cyclin), encoded by WDSV, has separable cyclin box and transcription activation domains. It binds to cyclin-dependent kinase 8 (CDK8) and enhances its kinase activity. CDK8 is evolutionarily conserved and is frequently overexpressed in human cancers. It is normally activated by cyclin C and is required for transcription elongation of the serum response genes (immediate early genes [IEGs]) FOS, EGR1, and cJUN. The IEGs drive cell proliferation, and their expression is brief and highly regulated. Here we show that constitutive expression of RV-cyclin in the HCT116 colon cancer cell line significantly increases the level of IEG expression in response to serum stimulation. Quantitative reverse transcription-PCR (RT-PCR) and nuclear run-on assays provide evidence that RV-cyclin does not alter the initiation of IEG transcription but does enhance the overall rate of transcription elongation and maintains transcription reinitiation. RV-cyclin does not increase activating phosphorylation events in the mitogen-activated protein kinase pathway and does not i...Continue Reading
References
Citations
Related Concepts
Related Feeds
Cell Checkpoints & Regulators
Cell cycle checkpoints are a series of complex checkpoint mechanisms that detect DNA abnormalities and ensure that DNA replication and repair are complete before cell division. They are primarily regulated by cyclins, cyclin-dependent kinases, and the anaphase-promoting complex/cyclosome. Here is the latest research.
Cancer Metabolism
In order for cancer cells to maintain rapid, uncontrolled cell proliferation, they must acquire a source of energy. Cancer cells acquire metabolic energy from their surrounding environment and utilize the host cell nutrients to do so. Here is the latest research on cancer metabolism.