Critical function of Ikaros in controlling Aiolos gene expression.
To characterize the regulation of lymphoid Aiolos transcription factor, we have cloned its promoter. Full promoter and nested deletions were expressed in lymphoid and non-lymphoid cell lines. The minimal promoter activity could be considered as a 172bp upstream from the ATG for Jurkat and HEK293 cells and as a 370bp fragment for U937 cells. Moreover, we have mapped the transcription initiation site. Retardation gels showed binding activity for Ikaros, NFkappaB and AP4 transcription factors and mutations in their binding sites abolish Aiolos promoter activity. Chromatin immunoprecipitation assay revealed that Ikaros, NFkappaB and AP4 are bound to Aiolos promoter. The important function of Ikaros and NFkappaB is underlined by their over expression, which results in the trans-activation of the promoter and drives Aiolos expression in cell lines and in freshly isolated B and T cells, while over expression of a dominant negative Ikaros isoform is able to block Aiolos expression.
Ghadiri
Ata
A
Immunologie Cellulaire et Tissulaire, Hôpital Pitié-Salpêtrière, Bâtiment CERVI, U543 Inserm, 83, Bd de l'Hôpital, 75013 Paris, France.
Duhamel
Marianne
M
Fleischer
Aarne
A
Reimann
Andreas
A
Dessauge
Frederic
F
Rebollo
Angelita
A
D001483:Base Sequence; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D004252:DNA Mutational Analysis; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D006801:Humans; D051740:Ikaros Transcription Factor / Q000378:metabolism*; D008214:Lymphocytes / Q000378:metabolism; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism; D011401:Promoter Regions, Genetic; D017384:Sequence Deletion; D014157:Transcription Factors / Q000235:genetics*; D024363:Transcription Initiation Site
C106285:IKZF3 protein, human; D016328:NF-kappa B; D014157:Transcription Factors; D051740:Ikaros Transcription Factor