Biopolymers and cell. 2010; 26 (2): 115 - 120
Identification and functional analysis of an alternative promoter of human intersectin 1 gene
S. V. Kropyvko, L. O. Tsyba, I. Ya. Skrypkina, A. V. Rynditch
Institute of Molecular Biology and Genetics NAS of Ukraine 150, Akademika Zabolotnogo Str., Kyiv, Ukraine, 03680
Aim. Intersectin 1 (ITSN1) gene encodes an evolutionarily conserved adaptor protein that functions in clathrin-mediated endocytosis, cell signalling, apoptosis and cytoskeleton rearrangements. Its expression is characterized by multiple alternative splicing. Alternative promoter usage is an additional way to create diversity and flexibility in the regulation of gene expression. The aim of this study was to identify possible alternative promoters of ITSN1 gene. Methods. In silico prediction, 5' RACE, RT-PCR and reporter gene expression assay were used for identification and functional characterization of alternative promoter region. Results. We detected an alternative promoter of human ITSN1 gene which is located in intron 5 and generates 5' truncated transcripts containing in-frame ATG codon with strong Kozak sequence and could encode an N-terminally truncated isoforms lacking first EH domain. The region located 246–190 bp upstream of exon 6 is required for alternative promoter activity. ITSN1 transcripts generated from an alternative promoter were detected in human kidney, liver, lung and brain tissues. However, the level of their expression was significantly lower than that of major ITSN1 isoforms. Conclusion. The results obtained suggest that alternative promoter region located in intron 5 of ITSN1 gene functions as a weak promoter. Further experiments are required to clarify the role of 5' truncated ITSN1 transcripts.
Keywords: intersectin 1, alternative promoter, alternative splicing, 5' UTR, adaptor proteins.