A partial cDNA clone for human apolipoprotein B.
A human liver cDNA library was screened for sequences coding for apolipoprotein B (apo B), the major protein of human low density lipoproteins. A mixture of synthetic oligonucleotides (26 bases long) coding for an amino acid sequence known to exist in apo B was used as a hybridization probe. A clone was identified that had a cDNA insert of 593 base pairs and that contained sequences coding for a peptide of 24 residues that had earlier been isolated from apo B by limited proteolysis. The entire nucleotide sequence of the cDNA insert consists of one open reading frame coding for 197 amino acids. Apo B-related RNAs were found in human liver, baboon liver, and the human hepatoma cell line HepG2. None were detected in placenta, simian virus 40 (SV40)-transformed fibroblasts, and a lymphoblastoid cell line. The length of the mature apo B mRNA was estimated to be 18 kb, enough to code for a protein with a molecular weight in the neighborhood of 500,000.
D000595:Amino Acid Sequence; D000818:Animals; D001055:Apolipoproteins B / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D006801:Humans; D008099:Liver; D012333:RNA, Messenger / Q000235:genetics
D001055:Apolipoproteins B; D012333:RNA, Messenger; D004247:DNA