AML1 (CBFalpha2) cooperates with B cell-specific activating protein (BSAP/PAX5) in activation of the B cell-specific BLK gene promoter.
AML1 plays a critical role during hematopoiesis and chromosomal translocations involving AML1 are commonly associated with different forms of leukemia, including pre-B acute lymphoblastic leukemia. To understand the function of AML1 during B cell differentiation, we analyzed regulatory regions of B cell-specific genes for potential AML1-binding sites and have identified a putative AML1-binding site in the promoter of the B cell-specific tyrosine kinase gene, blk. Gel mobility shift assays and transient transfection assays demonstrate that AML1 binds specifically to this site in the blk promoter and this binding site is important for blk promoter activity. Furthermore, in vitro binding analysis revealed that the AML1 runt DNA-binding domain physically interacts with the paired DNA-binding domain of BSAP, a B cell-specific transcription factor. BSAP has been shown previously to be important for B cell-specific regulation of the blk gene. Physical interaction of AML1 with BSAP correlates with functional cooperativity in transfection studies where AML1 and BSAP synergistically activate blk promoter transcription by more than 50-fold. These results demonstrate physical and functional interactions between AML1 and BSAP and suggest that AML1 is an important factor for regulating a critical B cell-specific gene, blk.
Libermann
T A
TA
New England Baptist Bone and Joint Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA.
Pan
Z
Z
Akbarali
Y
Y
Hetherington
C J
CJ
Boltax
J
J
Yergeau
D A
DA
Zhang
D E
DE
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D051017:Apoptosis Regulatory Proteins; D001402:B-Lymphocytes / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics*; D002460:Cell Line; D050676:Core Binding Factor Alpha 2 Subunit; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D051379:Mice; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism*; D051757:PAX5 Transcription Factor; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C111741:Bik protein, mouse; D002352:Carrier Proteins; D050676:Core Binding Factor Alpha 2 Subunit; D004268:DNA-Binding Proteins; D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; D051757:PAX5 Transcription Factor; C497281:PAX5 protein, human; C497282:Pax5 protein, mouse; D011518:Proto-Oncogene Proteins; C493728:RUNX1 protein, human; C493726:Runx1 protein, mouse; D014157:Transcription Factors