The RING Finger Protein RNF4, a Co-regulator of Transcription, Interacts with the TRPS1 Transcription Factor

• Published in: The Journal of biological chemistry Vol. 278; no. 40; pp. 38780 - 38785
• Main Authors: Kaiser, Frank J., Möröy, Tarik, Chang, Glenn T.G., Horsthemke, Bernhard, Lüdecke, Hermann-Josef
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 03.10.2003; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Motifs; Amino Acids - chemistry; Animals; beta-Galactosidase - metabolism; Blotting, Western; Cell Nucleus - metabolism; Cells, Cultured; COS Cells; DNA, Complementary - metabolism; DNA-Binding Proteins - metabolism; Gene Expression Regulation; Genes, Reporter; Humans; Luciferases - metabolism; Mice; Microscopy, Confocal; Microscopy, Fluorescence; Models, Genetic; Mutation; Neoplasm Proteins; Nuclear Proteins - metabolism; Precipitin Tests; Protein Binding; Protein Structure, Tertiary; Repressor Proteins; Transcription Factors; Transcription, Genetic; Transfection; Two-Hybrid System Techniques; Ubiquitin-Protein Ligases
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M306259200

The TRPS1 gene encodes a repressor of GATA-mediated transcription. Mutations in this gene cause the tricho-rhino-phalangeal syndromes, but the affected pathways are unknown. In a yeast two-hybrid screen with the C-terminal part of the murine Trps1 protein as bait, we obtained three yeast clones encoding two overlapping fragments of the 194 amino acids RING finger protein 4 (Rnf4). The overlap narrows down the Trps1-binding region within Rnf4 to amino acids 6-65. This region in Rnf4 is also known to interact with several proteins including steroid receptors. By using truncated Trps1 constructs, the Rnf4-binding region in Trps1 could be assigned to amino acids 985-1184 of 1281. This 200 amino acid region of Trps1 does not contain any predicted protein-protein interacting motif. Complex formation between the human proteins TRPS1 and RNF4 was verified by co-immunoprecipitation from transfected and native mammalian cells. Confocal laser-scanning microscopy revealed that the endogenous proteins are located in distinct structures of the nucleus. Using a luciferase reporter assay, we could demonstrate that the repressional function of TRPS1 is inhibited by RNF4. This finding suggests that RNF4 is a negative regulator of TRPS1 activity.