Control of MYEOV protein synthesis by upstream open reading frames.
The myeov gene has been isolated by the tumorigenicity assay and is localized at chromosome 11q13, a frequent site for chromosomal rearrangements in various carcinomas and B-cell neoplasms. In addition, myeov is coamplified with cyclin D1 and overexpressed in carcinomas of various organs. The mechanisms of myeov regulation remain enigmatic. The 5'-untranslated region (5'-UTR) of the myeov gene is long, encompasses several upstream AUGs, and is predicted to fold in a strong secondary structure, suggesting that its translation might be regulated by an internal ribosomal entry site. Here we show that initial experiments using monocistronic and dicistronic reporter constructs supported this assumption. However, the application of in vitro transcription/translation assays, Northern blot analysis, and promoterless dicistronic constructs revealed promoter activity of the myeov 5'-UTR. DNA transfection of dicistronic DNA constructs, normal and mutated forms of myeov cDNA fragments cloned in a eukaryotic expression vector, and direct RNA transfection analysis revealed that upstream AUG triplets in the 5'-UTR of the myeov transcript abrogate translation. Alternative splicing mechanisms in specific cell types and/or developmental stage may evade this translation control. Control experiments suggest that the 5'-UTR from encephalomyocarditis virus, when inserted at the midpoint of a dicistronic vector, is also able to function as a cryptic promoter.
de Almeida
Rogério Alves
RA
Institute of Human Genetics, University of Heidelberg, Germany.
Heuser
Tanja
T
Blaschke
Rüdiger
R
Bartram
Claus R
CR
Janssen
Johannes W G
JW
D020121:5' Untranslated Regions; D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D002880:Chromosomes, Human, Pair 11; D019938:Cyclin D1 / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004686:Encephalomyocarditis virus / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D005822:Genetic Vectors; D006801:Humans; D015151:Immunoblotting; D008156:Luciferases / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D015513:Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics*; D016366:Open Reading Frames; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D017433:Protein Structure, Secondary; D011518:Proto-Oncogene Proteins; D012313:RNA / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection
D020121:5' Untranslated Regions; D018076:DNA, Complementary; C407245:MYEOV protein, human; D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D019938:Cyclin D1; D012313:RNA; D004247:DNA; D008156:Luciferases