Crlz1 activates transcription by mobilizing cytoplasmic CBFbeta into the nucleus.
Transcriptional function of a novel Crlz1 protein was examined by using the CBF site-containing IgJ enhancer, because it was originally cloned due to its ability to bind CBFbeta, a subunit of CBF heterodimer, of which Runx is the other subunit. In a cotransfection experiment, Crlz1 was shown to increase the IgJ enhancer activity due to its CBF sites, as verified by both the absence of Crlz1 effect on the CBF-site mutated IgJ enhancer and the presence of transcriptional synergy between Crlz1 and CBFbeta. Most significantly, the cytoplasmic CBFbeta was shown to be mobilized into the nucleus when it was coexpressed with the nuclear Crlz1. This mobilized nuclear CBFbeta could then heterodimerize with the nuclear Runx to bind to its target DNA site with a high affinity. Furthermore, in our coimmunoprecipitation and chromatin immunoprecipitation experiments, Crlz1 was found to be bound to the resulting CBF heterodimer in a form of ternary complex and to remain in that ternary complex even when CBF bound to its target DNA site such as IgJ enhancer.
Park
Sung-Kyun
SK
Graduate School of Biotechnology, Institute of Life Science and Resources, Kyung Hee University, 1 Seocheon, Giheung, Yongin, Gyeonggi-do 446-701, Republic of Korea.
Lim
Jung-Hyun
JH
Kang
Chang-Joong
CJ
D021581:Active Transport, Cell Nucleus; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D050657:Core Binding Factor alpha Subunits / Q000235:genetics / Q000378:metabolism; D050658:Core Binding Factor beta Subunit / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000235:genetics; D007144:Immunoglobulin J-Chains / Q000235:genetics; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D034741:RNA, Small Interfering / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection
C493693:Cbfb protein, mouse; D050657:Core Binding Factor alpha Subunits; D050658:Core Binding Factor beta Subunit; C435748:Crlz1 protein, mouse; D004268:DNA-Binding Proteins; D007144:Immunoglobulin J-Chains; D008164:Luminescent Proteins; D009419:Nerve Tissue Proteins; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors