The HSS3/4 enhancer of Crlz1-IgJ locus is another target of EBF in the pre-B cell stage of B cell development.
The HSS3/4 enhancer of Crlz1-IgJ locus was first characterized with regard to the activity of HSS1 IgJ promoter in the plasma cells, where both of HSS3/4 enhancer and HSS1 IgJ promoter were found to be opened simultaneously to drive the IgJ gene expression. Unexpectedly, the HSS3/4 enhancer was also found to be opened in the pre-B cells. However, this opening of HSS3/4 enhancer in the pre-B cells could not be related to the IgJ gene expression, because neither the IgJ promoter was opened nor its gene was expressed at the pre-B cell stage of B cell development. Instead, it was postulated that the opened HSS3/4 enhancer might act on some other nearby promoter in pre-B cells, which is now guessed to be the Crlz1 promoter located at 22.5 kb from it. In consistence with this pre-B cell-specific opening of the HSS3/4 enhancer, a pre-B cell-specific in vivo footprint on a sequence similar to the EBF-binding consensus was detected within the enhancer. In this paper, we show that the protein causing the pre-B cell-specific in vivo footprint on a sequence similar to the EBF-binding consensus is truly EBF as judged by EMSA using various oligo-DNA competitors and anti-EBF antibodies. Also, as expected from other previous reports, EBF was shown to be expressed highly in pre-B cells, but very little or not in immature B, mature B and plasma cells using both the cell lines and FACS-sorted normal primary cells. Convincingly, mutations within the EBF site of HSS3/4 enhancer were shown to significantly impair the HSS3/4 enhancer activity in the pre-B cells, but not in the plasma cells.
Kim
Ja-Yeon
JY
Graduate School of Biotechnology, Institute of Life Science and Resources, Kyung Hee University, Yongin, Gyeonggi-do 449-701, Republic of Korea.
Park
Sung-Kyun
SK
Kim
Hong-Gi
HG
Cho
Sun-Jung
SJ
Kim
Jiyoung
J
Kang
Chang-Joong
CJ
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology*; D001483:Base Sequence; D015153:Blotting, Western; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D005434:Flow Cytometry; D007144:Immunoglobulin J-Chains / Q000235:genetics / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*
C435748:Crlz1 protein, mouse; D004268:DNA-Binding Proteins; C489921:Ebf1 protein, mouse; D007144:Immunoglobulin J-Chains; D009419:Nerve Tissue Proteins; D015534:Trans-Activators; D014157:Transcription Factors