The aim of this proposal is to analyse the role of the recently discovered transcription factors of the E2F and DP gene families in the control of cell proliferation and in tumourgenesis.
In mammalian cells, ordered progression through the individual phases of the cell cycle is regulated by check-point control mechanisms, which ascertain that only normal cells will replicate, and therefore are essential for the maintenance of genetic stability. Loss of check-point control predisposes mammalian cells to cancer, emphasising the critical role of cell cycle regulators for neoplastic disease. Many genes implicated in cell cycle regulation are controlled by a group of heterodimeric transcription factors, composed of proteins encoded by the E2F and DP gene families, respectively. Thus, tight regulation of E2F/DP activity may play a key-role in oncogenesis.
In a first step, it is planned to identify and characterise the main cellular target genes controlled by the E2F/DP family of transcription factors. In several model systems based on synchronised cultured cells, a thorough analysis of cell cycle regulation of gene expression through E2F/DP proteins will be performed; particular attention will be paid to the question whether differences can be found between E2F sites present in distinct target genes, or whether differential timing of E2F-driven gene expression is determined by complex regulatory elements, involving other DNA binding proteins besides E2F. To understand regulation of E2F/DP activity, the expression of different E2F and DP genes during the cell cycle and in different tissues will be analysed. In addition, we will analyse the role of post-translational modification, e.g. phosphorylation of E2F/DP proteins, and their interaction with other cellular proteins, including the products of oncogenes and tumour suppressor genes. Furthermore, the consequences of over-expression of different E2F/DP genes in various cell types will be studied, to establish the oncogenic potential of individual family members, alone or in combination with other gene products. These studies should provide an integrated view of transcriptional regulation during the cell cycle and cell differentiation, and allow us to design novel strategies to unravel the role of the E2F/DP regulatory network for growth control in normal and tumour cells.
In a second step, we intend to directly address the role of E2F/DP genes in tumourgenesis : it was shown recently that major cell cycle regulatory genes, including various cyclins, cdks and their inhibitors, are altered in a variety of human cancers. However, changes in the structure or expression of the E2F/DP genes in tumours were not reported. To address this question, a series of clinical specimens will be screened for genetic alterations in the gene encoding E2F-1 through E2F-5 and DP-1 through DP-3. Furthermore, we will establish a transgenic mouse model to study the involvement of E2F/DP genes in human cancer, including T-cell lymphoma.
Funding SchemeCSC - Cost-sharing contracts
1066 CX Amsterdam
G12 8QQ Glasgow
CB2 1QR Cambridge