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General Comment |
Molecular cloning and characterization of a human AIF-like gene with ability to induce apoptosis Xie Q, et al .
In this study, we cloned and characterized a human gene homologous to the apoptosis-inducing factor (AIF), which is named AIF-like (AIFL). Human AIFL has 598 amino acids, with a characteristic Rieske domain and a pyridine nucleotide-disulphide oxidoreductase domain (Pyr_redox). AIFL shares 35% homology with AIF, mainly in the Pyr_redox domain. RT-PCR analysis showed the expression of AIFL mRNA in all tissues tested, i.e., brain, colon, heart, kidney, liver, lung, muscle, ovary, pancreas, placenta, small intestine and testis. We developed antibodies against human AIFL using fusion proteins as antigens. The antibodies specifically recognized the antigen and heterologously expressed AIFL proteins. The expression of AIFL proteins in human tissues was also ubiquitous, demonstrated by immunohistochemistry in tissue array slides. Subcellular fractionation and immunofluorescence staining studies revealed that AIFL is predominantly localized to the mitochondria. Similar to AIF, overexpression of AIFL induced apoptosis, as shown by increased cytoplasmic nucleosomes and subdiploid cell populations in AIFL transfected cells. The segment 1-190 containing the Rieske domain induced apoptosis while the segment containing the Pyr_redox domain did not contribute to the pro-apoptotic function. The mitochondrial membrane potential of cells transfected with AIFL was significantly more depolarized than that of the control. AIFL transfection induced cytochrome C release and cleavage of caspase 3. Furthermore, the pan-caspase inhibitor z-VAD.fmk inhibited AIFL induced apoptosis. In summary, AIFL induces apoptosis in a caspase-dependent manner when heterologously expressed.
NCBI Summary:
The protein encoded by this gene has significant homology to NADH oxidoreductases and the apoptosis-inducing factor PDCD8/AIF. Overexpression of this gene has been shown to induce apoptosis. The expression of this gene is found to be induced by tumor suppressor protein p53 in colon caner cells.
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