The human c-myc exon 1 product: preparation of antisera and analysis of its expression.
We investigated the coding capacity of the previously reported open reading frame (ORF) of the human c-myc exon 1. By in vitro translation assay, we found that exon 1 ORF was translated into a 20-kd protein (p20 protein). In order to obtain antisera raised against the p20 protein, we constructed a plasmid vector which expressed most of the exon 1 ORF as a 25-kd (P25) protein in Escherichia coli. Polyclonal antisera raised against this P25 protein specifically precipitated a chimeric protein which contained exon 1-related amino acid sequences. We used these antisera to test for the existence of an exon 1 product in human cells. In the human cell lines tested, these antisera have failed so far to detect any exon 1-related proteins. However, exon 1-related proteins were detected with the anti-p20 antisera in quail embryonic cells (QEC) transfected by human c-myc recombinants constructed to express such proteins, but were expressed at low levels compared with the human c-myc protein also expressed in the transfected QEC. Our results suggest that secondary structure of the mRNA could be responsible for the low expression of the exon 1 product in QEC.
Ferré
F
F
INSERM Unité 186/CNRS UA 04 1160, Institut Pasteur, Lille, France.
Martin
P
P
Lagrou
C
C
Raes
M B
MB
Ghysdael
J
J
Saule
S
S
Stéhelin
D
D
D000818:Animals; D003370:Coturnix; D005091:Exons; D005786:Gene Expression Regulation; D006801:Humans; D007158:Immunologic Techniques; D008970:Molecular Weight; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000276:immunology; D014407:Tumor Cells, Cultured
D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins