Investigation on Subcellular Localization of BCL3 Transcription Coactivator
XIE Yecheng1, GUO Yilin1, LI Xuelu1, GAO Jingtao1, ZHANG Shuo1, DUAN Liangwei1,2, NIU Yuna1,2*
BCL3 transcriptional coactivator functions through binding with p50 or p52 homodimers, which plays roles in regulating cell cycle, promoting cell survival and inhibiting cell apoptosis. It has been revealed that abnormal expression of BCL3 proto-oncogene correlates with the occurrence and development of many cancers. Localization of BCL3 in cells is related to its function, while its subcellular localization and regulatory mechanism are still unclear. The aim of this study was to investigate the subcellular localization of BCL3 transcription coactivator in HeLa cells. Predication of subcellular localization of BCL3 protein was carried out using database and online software. A series of BCL3 gene deletion mutants were constructed and transfected into HeLa cells, and protein expression was confirmed by Western blot. Golgi, mitochondria and endoplasmic reticulum were labeled by indirect immunofluorescence assay, and the co-localization of BCL3 with these organelles was observed by confocal fluorescence microscopy. The results showed that BCL3 protein was dispersed, spotted and nuclear localized in different cells; the N-terminal domain (134-237 aa) played a decisive role in the nuclear localization of BCL3 protein; the C-terminal domain (338-454 aa) affected the formation of BCL3 protein spots; BCL3 and endoplasmic reticulum showed a high proportion of co-localization. These findings revealed the subcellular localization of BCL3 and its determining domain, which provided a basis for further studying the function of BCL3.
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