Lamprey Fibrinogen y Chain: Cloning, cDNA Sequencing, and General Characterization

D. D. Strong, M. Moore, B. A. Cottrell, V. L. Bohonus, M. Pontes, B. Evans, M. Riley, R. F. Doolittle

    Research output: Contribution to journalArticlepeer-review

    34 Scopus citations


    A cDNA library from lamprey liver was constructed in pBR322 and screened with a synthetic mixed oligonucleotide probe, the sequence of which was based on a partial amino acid sequence of the lamprey fibrinogen γ chain determined by conventional procedures. Among the positive clones was one containing a 600-base insert that covered the carboxy-terminal third of the chain and another with a 1950-base insert that stretched more than full length. The two inserts were sequenced by the Maxam-Gilbert procedure. The DNA sequencing was corroborated by reference to the amino acid sequences of five cyanogen bromide peptides that compose the carboxy-terminal 130 amino acids, as well as to a number of tryptic peptides from elsewhere in the molecule. The clone with the smaller insert (6G) contained 594 nucleotides (not counting G and C tails), 435 of which are coding and correspond to residues 264-408 of the 7 chain. The remaining 159 nucleotides included the terminator codon followed by a noncoding segment. The larger clone (2E) coded for 408 amino acids that could be readily aligned with the 411-residue human 7 chain. A 24-residue signal peptide adjacent to the proposed amino terminal was also inferred. The amino acid sequence of the fibrinogen 7 chain has been differentially conserved during evolution, the lamprey and human sequences being more than 70% identical in certain key regions but dropping to less than 25% in other sections, including the segment thought to be a part of the "coiled coils". Overall, the resemblance amounts to 50% identity. Of the 10 cysteines found in mammalian chains, 9 are at identical positions, but the tenth, which in mammalian fibrinogens is a part of the interdimeric bridging, is absent in the lamprey.

    Original languageEnglish (US)
    Pages (from-to)92-101
    Number of pages10
    Issue number1
    StatePublished - Jan 1 1985

    All Science Journal Classification (ASJC) codes

    • Biochemistry


    Dive into the research topics of 'Lamprey Fibrinogen y Chain: Cloning, cDNA Sequencing, and General Characterization'. Together they form a unique fingerprint.

    Cite this