Domains with transcriptional regulatory activity within the ALL1 and AF4 proteins involved in acute leukemia.
The ALLI gene, located at chromosome band 11q23, is involved in acute leukemia through a series of chromosome translocations and fusion to a variety of genes, most frequently to A4 and AF9. The fused genes encode chimeric proteins proteins. Because the Drosophila homologue of ALL1, trithorax, is a positive regulator of homeotic genes and acts at the level of transcription, it is conceivable that alterations in ALL1 transcriptional activity may underlie its action in malignant transformation. To begin studying this, we examined the All1, AF4, AF9, and AF17 proteins for the presence of potential transcriptional regulatory domains. This was done by fusing regions of the proteins to the yeast GAL4 DNA binding domain and assaying their effect on transcription of a reporter gene. A domain of 55 residues positioned at amino acids 2829-2883 of ALL1 was identified as a very strong activator. Further analysis of this domain by in vitro mutagenesis pointed to a core of hydrophobic and acidic residues as critical for the activity. An ALL1 domain that repressed transcription of the reporter gene coincided with the sequence homologous to a segment of DNA methyltransferase. An AF4 polypeptide containing residues 480-560 showed strong activation potential. The C-terminal segment of AF9 spanning amino acids 478-568 transactivated transcription of the reporter gene in HeLa but not in NIH 3T3 cells. These results suggest that ALL1, AF4, and probably AF9 interact with the transcriptional machinery of the cell.
Prasad
R
R
Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Yano
T
T
Sorio
C
C
Nakamura
T
T
Rallapalli
R
R
Gu
Y
Y
Leshkowitz
D
D
Croce
C M
CM
Canaani
E
E
D000208:Acute Disease; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002871:Chromosome Banding; D002874:Chromosome Mapping; D002880:Chromosomes, Human, Pair 11; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004330:Drosophila / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D007700:Kinetics; D007938:Leukemia / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D051788:Myeloid-Lymphoid Leukemia Protein; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011519:Proto-Oncogenes; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D016385:TATA Box; D014157:Transcription Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D035602:Transcriptional Elongation Factors; D014178:Translocation, Genetic; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; C497422:KMT2A protein, human; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; D051788:Myeloid-Lymphoid Leukemia Protein; C081449:AFF1 protein, human; D011495:Histone-Lysine N-Methyltransferase