ABSTRACT
Eukaryotic translation initiation factor 5A (eIF5A) is thought to function as a nucleocytoplasmic shuttle protein. There are reports of its involvement in cell proliferation, and more recently it has also been implicated in the regulation of apoptosis. In the present study, we examined the effects of eIF5A over-expression on apoptosis and of siRNA-mediated suppression of eIF5A on expression of the tumour suppressor protein, p53. Over-expression of either eIF5A or a mutant of eIF5A incapable of being hypusinated was found to induce apoptosis in colon carcinoma cells. Our results also indicate that eIF5A is required for expression of p53 following the induction of apoptosis by treatment with Actinomycin D. Depiction of eIF5A localization by indirect immunofluorescence has indicated, for the first time, that the protein is rapidly translocated from the cytoplasm to the nucleus by death receptor activation or following treatment with Actinomycin D. These findings collectively indicate that unhypusinated eIF5A may have pro-apoptotic functions and that eIF5A is rapidly translocated to the nucleus following the induction of apoptotic cell death.
Subject(s)
Cell Nucleus/metabolism , Colonic Neoplasms/metabolism , Peptide Initiation Factors/metabolism , RNA-Binding Proteins/metabolism , Signal Transduction , Tumor Necrosis Factor-alpha/pharmacology , Apoptosis , Cell Line, Tumor , Cell Proliferation , Colonic Neoplasms/pathology , Dactinomycin/pharmacology , Gene Expression Regulation, Neoplastic , Humans , Immunohistochemistry , Nitroprusside/pharmacology , Peptide Initiation Factors/genetics , Peptide Initiation Factors/physiology , RNA, Small Interfering/pharmacology , RNA-Binding Proteins/genetics , RNA-Binding Proteins/physiology , Transfection , Tumor Suppressor Protein p53/metabolism , Eukaryotic Translation Initiation Factor 5AABSTRACT
Cystic fibrosis (CF) is one of the most common recessive genetic diseases in North America. So far, 1200 mutations causing CF have been identified. Several techniques such as allele specific oligonucleotide (ASO) dot-blot, reverse dot-blot, amplification refractory mutation (ARMS), and an oligo-ligation assay, are available to detect the most common mutations. However, detecting compound heterozygotes between DeltaF508, the most common disease causing mutation, and other mutations which are rare is difficult as some mutations are common only to particular ethnic groups. Therefore, new diagnostic tests such as restriction enzyme assays and single stranded conformational polymorphism (SSCP) have been designed to recognize rare and population-specific mutations. This review will describe the most commonly used CF mutation detecting diagnostic techniques, as well as novel assays and techniques currently in development that might be employed in future.
