Krab zinc finger proteins and nuclear receptors

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Project objective

Research objectives and content: Human KRAB zinc finger proteins (KRAB ZFPs) represent a large subfamily of ZFPs of the Kruppel Cys2His2 (C2H2)-type containing a Krueppel associated box (KRAB) domain in their amino termini. Based on the finding that the KRAB domain can silence transcription when fused to a heterologous DNA binding domain in transiently transfected mammalian cells, the KRAB ZFPs have been postulated to function as negative regulators of transcription in many levels of cellular growth and differentiation. However, there is also the possibility that they participate in more general functions concerning structure and organisation of chromosomes. Recently, two specific KRAB-interacting proteins have been identified and characterized: TIF1alpha and TIF1a, which both belong to the same gene family and have many of the properties expected for corepressors acting at the chromatin level. TIF1alpha but not TIF1a was shown to interact directly with the ligand-dependent transcriptional activation function AF2 of nuclear receptors (NRs), indicating that some members of the TIF1 gene family may play a dual role in transcription, being involved in both repression by KRAB ZFPs and reactivation by agonist-bound NRs The aim of this project is to address the biological significance of the KRAB ZFP-TIF1 and TIF1-NR interactions. Training content: We will performed a yeast two hybrid screen using the KRAB-interacting domains of TIFlalpha and TIF1a as individual baits and a mouse embryo cDNA expression library. By this approach, mouse cDNAs encoding KRAB ZFPs that interact specifically with TIF1alpha and/or TIF1a will be identified and characterized. The corresponding genomic DNAs will be isolated for the subsequent disruption of the individual genes in mouse. The consequence(s) of these null mutations on development, cell differentiation and gene induction by nuclear receptors will be investigated. In addition, an in vitro transcription and chromatin assembly system that supports KRAB-mediated repression will be established and investigated for hormone-dependent reactivation. Links with industry/industrial relevance: We expect the project to result in the identification of new genes encoding regulatory proteins, some of which might be associated with specific human diseases. Therefore, the project will provide the basis for the development of new diagnostic and therapeutic concepts.

Original text from CORDIS.

Participants

• CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE · PARISCoordinatorFrance

Links

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