Multiple domains participate in distance-independent LAZ3/BCL6-mediated transcriptional repression.
The LAZ3/BCL6 gene implicated in diffuse large cell lymphomas encodes a transcriptional repressor containing Krüppel-fike zinc fingers. It harbours at its N-terminus a conserved protein/protein interaction motif, the BTB/POZ domain, which is also an autonomous transcriptional repression domain. We demonstrate here using several GAL4-LAZ3/BCL6 chimeras that the BTB/POZ domain plays an important but not exclusive role as its deletion gives rise to a GAL4 chimera that mediates significant, albeit reduced, transcriptional repression. Moreover, the repressive effect mediated either by LAZ3/BCL6 or by the isolated domains occurs with unaltered efficiency even at long distance (1.6 Kbp), ruling out steric hindrance mechanisms. Finally, though the absence of a TATA box appears to weaken this activity, it is largely promoter independent. Taken together, our results demonstrate that multiple domains participate in the promoter and distance-independent LAZ3/BCL6-mediated transcriptional repression.
Albagli
O
O
Institut de Recherches sur le Cancer de Lille, France.
Dhordain
P
P
Bernardin
F
F
Quief
S
S
Kerkaert
J P
JP
Leprince
D
D
D000818:Animals; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000096:biosynthesis; D005786:Gene Expression Regulation; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse; D009132:Muscles; D016296:Mutagenesis; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051560:Proto-Oncogene Proteins c-bcl-6; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D016385:TATA Box; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D011518:Proto-Oncogene Proteins; D051560:Proto-Oncogene Proteins c-bcl-6; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D015500:Chloramphenicol O-Acetyltransferase