The 5' part of the human H19 RNA contains cis-acting elements hampering its translatability.
H19 is an imprinted gene developmentally regulated in man and mouse and implicated in various neoplasms. No corresponding protein product has yet been detected, although several open reading frames (ORFs) could be identified along its RNA. The largest ORF found in the human gene could encode a putative 26 kDa protein. We have isolated two H19 cDNAs (AP and ES) that contain this ORF4 and correspond to incomplete copies of the unique 2.3 kb H19 RNA. In transient expression assays, AP was able to synthesize a 26 kDa protein whereas ES was not. With respect to ORF4, ES exhibits a 536 bp long GC-rich 5' untranslated region, whereas AP contains the last 22 nucleotides of this 5'UTR. Using deletions and point mutations, we have found that the length and probably the secondary structure of the 5'UTR strongly hampers the translatability of the RNA. In addition, a potential role of upstream ORFs (uORFs) was detected as stressed by the enhances translation of a construct mutated in uORF3 overlapping ORF4. Interactions between H19 and proteins are indicated by a specific binding between 5'UTR derived RNA segments and two nuclear proteins of about 27 kDa. Our results favor a potential role of these particular structures and binding properties in general trans-regulation of RNA post-transcriptional processes rather than in normal control of H19 mRNA translation.
Joubel
A
A
CNRS URA 1160, Institut Pasteur de Lille, France.
Curgy
J J
JJ
Pelczar
H
H
Begue
A
A
Lagrou
C
C
Stehelin
D
D
Coll
J
J
D000818:Animals; D019556:COS Cells; D002645:Chickens; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression; D018392:Genomic Imprinting; D006801:Humans; D051379:Mice; D009124:Muscle Proteins / Q000235:genetics*; D009154:Mutation; D009687:Nuclear Proteins / Q000145:classification / Q000378:metabolism; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D010802:Phylogeny; D011485:Protein Binding; D014176:Protein Biosynthesis; D062085:RNA, Long Noncoding; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D022661:RNA, Untranslated; D016601:RNA-Binding Proteins / Q000145:classification / Q000378:metabolism; D051381:Rats; D012045:Regulatory Sequences, Nucleic Acid; D017384:Sequence Deletion
D018076:DNA, Complementary; C094335:H19 long non-coding RNA; D009124:Muscle Proteins; D009687:Nuclear Proteins; D062085:RNA, Long Noncoding; D012333:RNA, Messenger; D022661:RNA, Untranslated; D016601:RNA-Binding Proteins