Structural basis of the interaction between P-element somatic inhibitor and U1-70k essential for the alternative splicing of P-element transposase.

P-element transposition in Drosophila is regulated by tissue-specific alternative splicing of the P-element transposase pre-mRNA. In somatic cells, the P-element somatic inhibitor (PSI) protein binds to exon 3 of the pre-mRNA and recruits U1 small nuclear ribonucleoprotein (snRNP) to the F1 pseudo-splice site. This abrogates binding of U1 snRNP to ...
the genuine 5' splice site, thereby preventing excision of the third intron. Two homologous short sequences, referred to as the A and B boxes, near the C terminus of PSI bind to U1-70k protein within U1 snRNP. We have now mapped the AB box-binding site of U1-70k to a short proline-rich sequence at the C terminus. Our NMR study shows that the B box forms an anti-parallel helical hairpin in which four highly conserved aromatic residues form a cluster on one face of the first helix. This hydrophobic cluster interacts extensively with the proline-rich region of the U1-70k protein.
Mesh Terms:
Alternative Splicing, Amino Acid Sequence, Base Sequence, Binding Sites, Drosophila Proteins, Exons, Introns, Magnetic Resonance Spectroscopy, Nuclear Proteins, Protein Binding, RNA Precursors, RNA-Binding Proteins, Ribonucleoprotein, U1 Small Nuclear, Transposases
J. Mol. Biol.
Date: Aug. 05, 2005
Download Curated Data For This Publication
203287
Switch View:
  • Interactions 2