PEBP2/PEA2 represents a family of transcription factors homologous to the products of the Drosophila runt gene and the human AML1 gene.

Abstract

ABSTRACTcDNAs representing the a subunit of polyomavirus enhancer binding protein 2 (PEBP2; also cafled PEA2) were isolated. The products of the cDNAs are highly homologous to that of Drosophila segmentation gene runt (run) for an N-proximal 128-amino acid region showing 66% identity. The run homology region encompasses the domain capable of binding to a specific nucleotide sequence motif and of dimerizing with the companion 13 subunit. The human AMLI gene related to t(8;21) acute myeloid leukemia also has a run homology region. Together with the 18 subunit, which increases the affinity of the a subunit to DNA without binding to DNA by itself, PEBP2 represents a newly discovered family of transcription factor. The major species of PEBP2a mRNA was expressed in T-cell lines but not in B-cell lines tested. Evidence indicated that PEBP2 functions as a transcriptional activator and is,involved in regulation of T-ceil-specific gene expression.Potential use of polyomavirus (Py) as a probe of mouse development has been recognized since it was observed that the wild-type Py did not grow in embryonal carcinoma cells but that it grew when the cells were induced to differentiate (1)(2)(3)(4)(5). Through the analysis of the Py enhancer, which determines the differentiation-dependent and cell-typespecific expression of the viral genes, a number of transcription factors involved in developmental regulation have been identified (6-10).PEBP2/PEA2, which binds to both the A and B cores of the Py enhancer (11), is undetectable in embryonal carcinoma F9 cells and becomes detectable after the cells are induced to differentiate (6,7). It specifically recognizes a consensus sequence, R/TACCRCA (R, purine), which was originally identified in the Py enhancer (11) and is also compatible with the core motif of murine leukemia virus enhancers (12,13). In addition, many T-cell-specific genes, such as T-cell receptor (TCR) a, X3, yand 8 and CD3e genes, contain potential PEBP2 binding sites, suggesting the possibility that PEBP2 is involved in T-cell-specific gene expression (13 [708][709][710][711][712][713][714]. The mutations are the same as the M2 mutation (14). For expression in mammalian cells, the coding regions of al, a2, and 831 cDNAs were cloned into the Xho I site of pCDMPy, in which the Py origin and enhancer region were deleted from pCDM8 (Invitrogen), resulting in pCDMPy-al, pCDMPy-a2, and pCDMPy-31. The bacterial expression plasmids pETal and pETa2, carrying the whole coding regions of al and a2 cDNAs, were constructed in the same way as pETf82 (16). To produce deletion mutants of a2, the whole coding region of a2 cDNA was inserted into the BamHI/HindIII fragment of plasmid pQE9 (Qiagen) resulting in pQE9-a2 encoding a fusion protein tagged with an N-terminal histidine cluster. Various deletions were introduced into pQE9-a2 using appropriate restriction sites: N94C306 encodes a region of aa 94-306; N1C226 encodes aa 1-226; N1C158 encodes aa 1-158; N80C226 encodes aa 80-226. N1C226, N1C158, and N80C226 proteins have one, two, o...

The cDNA cloning of the transcripts of human PEBP2αA/CBFA1 mapped to 6p12.3-p21.1, the locus for cleidocranial dysplasia

“…In order to isolate human cDNAs encoding the Runt domain of PEBP2, we screened the cDNA library prepared from a human T-cell line using, as a probe, the mouse cDNA fragment containing the Runt domain region of PEBP2aA1 (Ogawa et al, 1993b). From this screening, the cDNA clones representing human PEBP2aA, PEBP2aB/AML1 and PEBP2aC were isolated.…”

“…One represented the human counterpart of the mouse major splice form, termed PEBP2aA1, characterized by the highly conserved ®ve amino acid sequence, VWRPY, at the extreme carboxy-terminus of the protein product (Ogawa et al, 1993b). The VWRPY motif is present not only in the major products of all three mammalian Runt domain genes but also in the products of Drosophila runt and lozenge as well as that of C. elegans runt (reviewed by Ito and Bae, 1997, in press).…”

“…The mouse PEBP2aA1 cDNA sequence that we reported earlier (Ogawa et al, 1993b) is also shown for comparison. Human and mouse PEBP2aA1 cDNAs are highly conserved.…”

“…The b subunit associates well with all three a subunits (Ogawa et al, 1993b;Bae et al, 1994Bae et al, , 1995. This means that structural alterations of any one of the a or b subunit genes would have potential to a ect the regulatory role of others.…”

“…There are three mammalian genes which encode the a subunit. They are PEBP2aA (Ogawa et al, 1993b), AML1/PEBP2aB (Bae et al, 1993(Bae et al, , 1994 and PEBP2aC (Bae et al, 1995;Levanon et al, 1994;Wijimenga et al, 1995). The a subunit contains the evolutionarily conserved 128 amino acid region termed the Runt domain responsible for the DNA binding and the heterodimerization activities .…”