Eukaryotic Chromatin Dynamics

Lead Research Organisation: MRC London Institute of Medical Sciences

Abstract

We are interested in the function of a group of evolutionarily conserved proteins called Cks proteins. Cks proteins are present in all eukaryotic cells and are expressed in all cell types in the body. Interestingly, they are frequently over-expressed in cancers. Cks1 proteins physically interact with the key regulators of the cell cycle but their precise function has remained elusive for many years. We recently showed a novel function of Cks proteins in regulating transcription, a fundamental cellular process that is key to life. We also found that this regulation involved an interaction with the cells protein degradation machinery. In this program we are interested in studying the function of Cks proteins using cellular systems and model organisms. Ultimately we wish to relate this information to cancer biology and therapy. By understanding the basic biology, we will address why these proteins are over-expressed in cancers and whether interfering with the function of these proteins would affect cancer progression and/or response to cancer therapy.

Technical Summary

The mission of a cell is to divide and faithfully propagate its genetic material. This requires many basic functions of life such as transcription and protein synthesis to be coordinated with the chromosome cycle. A complex regulatory network ensures this, and aberrations in the control of any of these pathways can contribute to carcinogenesis.||This project specifically aims to understand the function of a group of small proteins, the Cks family, that interact closely with the main drivers of the cell cycle, the cyclin-dependent kinases (CDKs). Cks proteins are highly conserved in eukaryotic evolution, being present in simple unicellular organisms such as yeast up to the most complex systems such as human beings. Cks1 proteins are frequently up-regulated in a wide-range of cancers.||Simple unicellular eukaryotes have a single Cks isoform (known as Cks1) that is either essential for normal growth. Complex eukaryotes such as humans have two isoforms, hCks1 and hCks2. While Cks proteins in all organisms bind tightly to CDK, their precise function is unknown.||In mammalian cells, the Cks1 protein (but not Cks2) serves as a specific adaptor for poly-ubiquitylation (and hence degradation) of the CDK inhibitor p27 by SCFSkp2. This serves as an important signal to drives cells into S phase of the cell cycle. In yeast, this adaptor function is not conserved. We have shown that yeast Cks1 plays a role in controlling transcription and chromatin structure through interaction with the cells protein degradation machinery, the proteasome. We are interested in investigating whether this transcription function is conserved in human cells. Using biochemical approaches to identify and characterise interacting proteins and by combining these studies with mouse genetics we aim to elucidate the conserved functions Cks proteins and identify the significance of Cks1 and Cks2 up-regulation in tumours.
 
Description CRUK funding (Cks proteins in Carcinogenesis)
Amount £150,000 (GBP)
Organisation Cancer Research UK 
Sector Charity/Non Profit
Country United Kingdom
Start 10/2007 
End 10/2010
 
Title Cks KOs 
Description Cks1 and Cks2 knockout mice are derived from ES cell clones from genetrap resources. 
Type Of Material Model of mechanisms or symptoms - mammalian in vivo 
Provided To Others? No  
Impact Allows us to study the function of cks proteins in primary cell lines and in vivo. 
 
Title Transcription/ drug screening tool 
Description Based on our research that Cks proteins possessed transcriptional activating activities, we have devised both a yeast based and a mammalian based screening tool for screening for small molecule compounds that inhibit Cks-mediated transcriptional activity. 
Type Of Material Technology assay or reagent 
Provided To Others? No  
Impact If successful in identifying new compounds, this could impact on important anti-cancer drug development as both Cks proteins are important novel oncogenes involved in multiple advanced tumours from multiple tissues. 
 
Description DNA Array 
Organisation Scripps Research Institute
Department DNA Array Core Facility
Country United States 
Sector Academic/University 
PI Contribution We provided cell culture samples for expression array analysis.
Collaborator Contribution Sharing expertise in science and technology
Impact Array data on Cancer model. Publication in preparation
Start Year 2007
 
Description DNA combing 
Organisation National Cancer Institute (NCI)
Country United States 
Sector Public 
PI Contribution Provided DNA samples for single molecular analysis.
Collaborator Contribution expertise and detailled array data on NCI60 cancer cell lines
Impact Established novel role of Cks2, a prime focus of our laboratory in regulation of replication fork velocity. Publication in preparation.
Start Year 2009
 
Description Proteomics 
Organisation University College London
Department Division of Medicine
Country United Kingdom 
Sector Academic/University 
PI Contribution Shared expertise in proteomics
Collaborator Contribution shared expertise in proteomics
Impact led to publication 19786724 and 20516216
Start Year 2006
 
Description Sussex 
Organisation University of Sussex
Department Genome Damage and Stability Centre
Country United Kingdom 
Sector Academic/University 
PI Contribution shared information and expertise
Collaborator Contribution shared information which has lead to publications
Impact Collaborative research led to publication of 19142183
Start Year 2007
 
Description clinical 
Organisation Cardiff University
Department School of Medicine
Country United Kingdom 
Sector Academic/University 
PI Contribution Clinical collaborators shared expertise in pathology and clinical information
Collaborator Contribution shared expertise in clinical and basic scienceshared expertiseshared information shared expertise and informationshared expertiseshared informationshared expertise
Impact led to publications 19142183 and 19493351
Start Year 2007
 
Description clinical 
Organisation London North West Healthcare NHS Trust
Department North West Thames Regional Genetics Service (Kennedy-Galton Centre)
Country United Kingdom 
Sector Public 
PI Contribution Clinical collaborators shared expertise in pathology and clinical information
Collaborator Contribution shared expertise in clinical and basic scienceshared expertiseshared information shared expertise and informationshared expertiseshared informationshared expertise
Impact led to publications 19142183 and 19493351
Start Year 2007
 
Description clinical 
Organisation Medical Research Council (MRC)
Department MRC Human Genetics Unit
Country United Kingdom 
Sector Public 
PI Contribution Clinical collaborators shared expertise in pathology and clinical information
Collaborator Contribution shared expertise in clinical and basic scienceshared expertiseshared information shared expertise and informationshared expertiseshared informationshared expertise
Impact led to publications 19142183 and 19493351
Start Year 2007
 
Description clinical 
Organisation Ninewells Hospital
Country United Kingdom 
Sector Hospitals 
PI Contribution Clinical collaborators shared expertise in pathology and clinical information
Collaborator Contribution shared expertise in clinical and basic scienceshared expertiseshared information shared expertise and informationshared expertiseshared informationshared expertise
Impact led to publications 19142183 and 19493351
Start Year 2007
 
Description clinical 
Organisation Royal Marsden NHS Foundation Trust
Country United Kingdom 
Sector Public 
PI Contribution Clinical collaborators shared expertise in pathology and clinical information
Collaborator Contribution shared expertise in clinical and basic scienceshared expertiseshared information shared expertise and informationshared expertiseshared informationshared expertise
Impact led to publications 19142183 and 19493351
Start Year 2007
 
Description clinical 
Organisation University College London
Department Department of Pathology
Country United Kingdom 
Sector Academic/University 
PI Contribution Clinical collaborators shared expertise in pathology and clinical information
Collaborator Contribution shared expertise in clinical and basic scienceshared expertiseshared information shared expertise and informationshared expertiseshared informationshared expertise
Impact led to publications 19142183 and 19493351
Start Year 2007
 
Description clinical 
Organisation University of East Anglia
Department School of Medicine UEA
Country United Kingdom 
Sector Academic/University 
PI Contribution Clinical collaborators shared expertise in pathology and clinical information
Collaborator Contribution shared expertise in clinical and basic scienceshared expertiseshared information shared expertise and informationshared expertiseshared informationshared expertise
Impact led to publications 19142183 and 19493351
Start Year 2007
 
Title Identification of a novel loss of function mutation in Cks2 in ovarian cancers 
Description We identified a novel loss of function mutation in the human Cks2 gene in a subset of ovarian cancers that is associated with high grade/stage. Principle funding: MRC and CRUK 
Type Diagnostic Tool - Non-Imaging
Current Stage Of Development Initial development
Year Development Stage Completed 2010
Development Status Under active development/distribution
Impact Based on our cellular studies and murine knockout model studies, we identified that Cks2 is involved in replication and its absence leads to an accumulation of DNA damage. However, to date the link between Cks2 and cancer has been restricted to over-expression. Establishment of a loss of function mutation of Cks2 in cancer samples provides a relevance for our model organism system in human disease. Further validation of this mutation in a larger cohort of cancers will identify how the prevalence of this mutation might be relevant as a prognostic marker for cancers. 
 
Title Identification of a novel mutagenic mutation in HNPCC 
Description Identification and verification of the function of a novel MLH1 mutation as mutagenic and which is associated with a unique spectrum of cancers 
Type Diagnostic Tool - Non-Imaging
Current Stage Of Development Initial development
Year Development Stage Completed 2008
Development Status Actively seeking support
Impact Patient kindred involved finally can ascribe their cancers to a pathogenic mutation inherited through the family. Implications for other families with the same mutation. 
 
Description Work experience for high school student 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Work experience for Scottish high school student in a biology lab. Introduction to use of model organisms in the study of the cell cycle.

Outreach to high school students
Year(s) Of Engagement Activity 2008