Attenuated function of a variant form of the helix-loop-helix protein, Id-3, generated by an alternative splicing mechanism

• Published in: FEBS letters 1996-09, Vol.393 (1), p.113-116
• Main Authors: Deed, Richard W., Jasiok, Michelle, Norton, John D.
• Format: Article
• Language: English
• Subjects: Adult; Alternative Splicing; B-Lymphocytes - cytology; Blotting, Northern; Cells, Cultured; Gene Expression; Genetic Variation; Helix-loop-helix; Helix-Loop-Helix Motifs; Humans; Inhibitor of Differentiation Proteins; Neoplasm Proteins; RNA - analysis; RNA splicing; Transcription factor; Transcription Factors - genetics; Transcription Factors - physiology
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(96)00868-X

The Id family of helix-loop-helix proteins function as negative regulators of DNA binding, basic helix-loop-helix proteins in the regulation of cell growth and differentiation. We report here on the identification of a 17 kDa variant of the 14 kDa Id-3 protein termed Id-3L (long version) which possesses a unique 60 amino acid carboxy-terminus generated by readthrough of a ‘coding intron’ and alternative splicing. Northern analysis revealed expression of a minor 1.1 kb Id-3L transcript together with the predominant 0.95 kd Id-3 transcript in the majority of adult human tissues analysed. The variant Id-3L protein is functionally distinguishable from conventional Id-3 since in in vitro DNA mobility shift assays, it was greatly impaired in its ability to abrogate binding of the basic helix-loop-helix protein, E47, to an E box recognition sequence.