title: cDNA sequences of two apolipoproteins from lamprey.
abstract: The messages for two small but abundant apolipoproteins found in lamprey blood plasma were cloned with the aid of oligonucleotide probes based on amino-terminal sequences. In both cases, numerous clones were identified in a lamprey liver cDNA library, consistent with the great abundance of these proteins in lamprey blood. One of the cDNAs (LAL1) has a coding region of 105 amino acids that corresponds to a 21-residue signal peptide, a putative 8-residue propeptide, and the 76-residue mature protein found in blood. The other cDNA (LAL2) codes for a total of 191 residues, the first 23 of which constitute a signal peptide. The two proteins, which occur in the "high-density lipoprotein fraction" of ultracentrifuged plasma, have amino acid compositions similar to those of apolipoproteins found in mammalian blood; computer analysis indicates that the sequences are largely helix-permissive. When the sequences were searched against an amino acid sequence data base, rat apolipoprotein IV was the best matching candidate in both cases. Although a reasonable alignment can be made with that sequence and LAL1, definitive assignment of the two lamprey proteins to typical mammalian classes cannot be made at this point.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001053:Apolipoproteins / Q000097:blood / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D003062:Codon; D004247:DNA / Q000032:analysis*; D007798:Lampreys; D009693:Nucleic Acid Hybridization; D051381:Rats; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001053:Apolipoproteins; D003062:Codon; D004247:DNA