Aly: Proteins and Enzymes

Pre-mRNA splicing plays an important role in regulation of gene expression. During the splicing process, specific proteins are recruited to the mRNA and assembled into a complex of mRNA-protein near the exon-exon junction. This complex is termed the mRNA-protein complex (mRNP) or the exon-exon junction complex. The proteins that are found in this complex include: Y14, magoh, Aly/REF, RNPS1, Upf3, and DEK.1-5 Aly (also known as mREF1-I) is the mammalian homologue of the yeast mRNA export factor Yra1p.6-7 It is a 233 amino acid RNAbinding protein that contains a RNA-binding domain and is recruited to the mRNP complexes during the splicing. Excess of recombinant expression of Aly in the cells increases both the rate and efficiency of spliced and unspliced mRNA export (in vivo) from the nucleus to the cytoplasm. In contrast to the Y14 protein, Aly is dissociated from the mRNAs after the export to the cytoplasm.1, 5-6