Location Of Nls-Rar Alpha Protein In Nb4 Cell And Nude Mice

In the majority of acute promyelocytic leukemia (APL) cases, translocons produce a promyelocytic leukemia protein-retinoic acid receptor a (PML-RAR alpha) fusion gene. Studies have reported that neutrophil elastase (NE) cleaves bcr-1-derived PML-RAa in early myeloid cells, leaving only the nuclear localization signal (NLS) of PML attached to RAR alpha. NLS-RAR alpha promotes cell growth and inhibits differentiation in response to ATRA. However, the mechanisms by which NLS-RAR alpha affects cell biological characteristics are yet to be fully elucidated. The present study found that the location of RARawas altered after it was cleaved by NE. Firstly, NE was overexpressed during the preparation of recombinant plasmid NB-4/pCMV6-NE-Myc to cleave PML-RAR alpha. The total protein expression levels of myc and NE and expression levels of NLS-RAR alpha in nucleoprotein were detected by western blotting. Location of NLS-RAR alpha protein was detected by immunofluorescence and confocal laser scanning. Secondly, a nude mice model was constructed and NE protein, NLS-RAR alpha and RAR alpha protein assays, and the location of NLS-RAR alpha and RAR alpha proteins were assessed as described. The present results showed that, compared with the control groups, the location of NLS-RAR alpha protein was predominantly detected in the nucleus, whereas RAR alpha was mainly distributed in the cytoplasm. These findings were consistent with those of the nude mice model, and these may be used as a foundation to explain the occurrence mechanism of APL.