Homeotic gene Antennapedia mRNA contains 5'-noncoding sequences that confer translational initiation by internal ribosome binding.
The Antennapedia (Antp) homeotic gene of Drosophila melanogaster has two promoters, P1 and P2. The resulting Antp mRNAs contain 1512-nucleotide (P1) and 1727-nucleotide (P2) 5'-noncoding regions, composed of exons A, B, D, and E (P1) or exons C, D, and E (P2), respectively. Multiple AUG codons are present in exons A, B, and C. We have found that 252-nucleotide exon D, common to mRNAs from both transcription units and devoid of AUG codons, can mediate initiation of translation by internal ribosome binding in cultured cells. Many mRNAs in Drosophila contain long 5'-noncoding regions with apparently unused AUG codons, suggesting that internal ribosome binding may be a common mechanism of translational initiation, and possibly its regulation, in Drosophila.
Department of Biochemistry, University of Colorado Health Sciences Center, Denver 80262.
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D000818:Animals; D051943:Antennapedia Homeodomain Protein; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D005801:Genes, Homeobox / Q000235:genetics*; D018398:Homeodomain Proteins; D009687:Nuclear Proteins / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D014176:Protein Biosynthesis / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics; D012270:Ribosomes / Q000378:metabolism*; D014157:Transcription Factors
D051943:Antennapedia Homeodomain Protein; C497974:Antp protein, Drosophila; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014157:Transcription Factors