Multiple mRNAs encode the murine translation initiation factor eIF-4E.
All eukaryotic cellular mRNAs (except organellar) possess at their 5' end the structure m7GpppX (where X is any nucleotide) termed the "cap." The cap structure facilitates the melting of mRNA 5' secondary structure through the action of initiation factor-4F (eIF-4F) in conjunction with eIF-4B. eIF-4F consists of three subunits of which one, eIF-4E (eIF-4E has recently been designated eIF-4 alpha according to the Nomenclature Committee of the International Union of Biochemistry (NC-IUB) (Safer, B. (1989) Eur. J. Biochem. 186, 1-3)), contains the cap binding site. Several lines of evidence suggest that eIF-4E regulates the rate of translation initiation. Consequently, changes in cellular eIF-4E levels could control growth and differentiation. To investigate the possibility that eIF-4E expression is regulated, we studied the pattern of eIF-4E expression in several cell lines. Here, we show the existence of multiple mRNAs for eIF-4E that are generated by differential polyadenylation. In addition, we show tissue-specific differences in eIF-4E mRNA expression and utilization of polyadenylation sites.
Jaramillo
M
M
Department of Biochemistry, McGill University, Montreal, Federal Republic of Germany.
Pelletier
J
J
Edery
I
I
Nielsen
P J
PJ
Sonenberg
N
N
D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D039561:Eukaryotic Initiation Factor-4E; D015870:Gene Expression; D051379:Mice; D008969:Molecular Sequence Data; D010448:Peptide Initiation Factors / Q000235:genetics* / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D014018:Tissue Distribution
D039561:Eukaryotic Initiation Factor-4E; D010448:Peptide Initiation Factors; D012333:RNA, Messenger; D004247:DNA