Apolipoprotein B-48 is the Product of a Messenger RNA with an Organ-Specific In-Frame Stop Codon

• Published in: Science (American Association for the Advancement of Science) Vol. 238; no. 4825; pp. 363 - 366
• Main Authors: Chen, San-Hwan, Habib, Geetha, Yang, Chao-Yuh, Gu, Zi-Wei, Lee, Bo Rong, Weng, Shi-ai, Silberman, Steven R., Cai, Sheng-Jian, Deslypere, J. P., Rosseneu, Maryvonne, Gotto, Antonio M., Li, Wen-Hsiung, Chan, Lawrence
• Format: Journal Article
• Language: English
• Published: Washington, DC The American Association for the Advancement of Science 16-10-1987; American Association for the Advancement of Science
• Subjects: Adults; Amino Acid Sequence; Amino acid sequencing; Amino acids; Apolipoprotein B-48; Apolipoproteins; Apolipoproteins B - genetics; Apolipoproteins B - metabolism; Base Sequence; Biochemistry; Biological and medical sciences; Chylous Ascites - metabolism; Codon; Complementary DNA; DNA - genetics; Fundamental and applied biological sciences. Psychology; Genetic aspects; Genetics; Humans; intestine; Intestine, Small - analysis; Intestines; Liver; man; Medical research; Messenger RNA; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Molecules; Nucleic Acid Hybridization; Nucleotide sequence; Peptide Fragments; Proteins; RNA; RNA, Messenger - analysis; RNA, Messenger - genetics; Sequencing; Stop codon; Transcription. Transcription factor. Splicing. Rna processing; Trypsin - metabolism; Human; Transcription termination; Messenger RNA; Nucleotide sequence; Gut; Tissue specificity; Stop codon; Lipoprotein; Apolipoproteins
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.3659919

The primary structure of human apolipoprotein (apo) B-48 has been deduced and shown by a combination of DNA excess hybridization, sequencing of tryptic peptides, cloned complementary DNAs, and intestinal messenger RNAs (mRNAs) to be the product of an intestinal mRNA with an in-frame UAA stop codon resulting from a C to U change in the codon CAA encoding Gln$^{2153}$ in apoB-100 mRNA. The carboxyl-terminal Ile$^{2152}$ of apoB-48 purified from chylous ascites fluid has apparently been cleaved from the initial translation product, leaving Met$^{2151}$ as the new carboxyl-terminus. These data indicate that $\sim $85% of the intestinal mRNAs terminate within $\sim $0.1 to 1.0 kilobase downstream from the stop codon. The other $\sim $15% have lengths similar to hepatic apoB-100 mRNA even though they have the same in-frame stop codon. The organ-specific introduction of a stop codon to a mRNA appears unprecedented and might have implications for cryptic polyadenylation signal recognition and RNA processing.