Cloning of a urochordate cDNA featuring mammalian short consensus repeats (SCR) of complement-control protein superfamily

Z. Pancer, H. Gershon, B. Rinkevich

Research output: Contribution to journalArticlepeer-review


Mammalian tumor necrosis factor (TNF)-α degenerate polymerase chain reaction (PCR) primers were used to amplify a probe from Botryllus schlosseri (colonial ascidian) allogeneic rejection-cDNA library. A PCR product (269 bp) was cloned and sequenced encoding an open reading frame (ORF) of 89 amino acids (aa). This clone, which revealed no similarity to TNF-α, but a substantial similarity to mammalian proteins featuring short consensus repeats (SCRs) of the complement control superfamily, was used to probe the rejection-cDNA library. Two partial cDNA clones were isolated and sequenced (Bs. 1, 846 bp; Bs.2, 712 bp). The longest ORF in clone Bs. 1 (which lacks the 5' end of the cDNA) predicts a protein of 251 aa, which differs from Bs.2 at six nucleotides and four aa. We compare the as similarity (up to 50.5%) of Bs.l with the SCR-region of mammalian complement factor H, apolipoprotein H, selectins, and complement receptors type 1 and type 2. A somatomedin B-like domain at the C-terminus of Bs. 1 deduced protein was also recorded. We propose that this mosaic and polymorphic botryllid sequence, featuring mammalian-like SCRs, might be an ancestral molecule in the evolution of the chordate's complement-control protein superfamily.

Original languageEnglish
Pages (from-to)625-632
Number of pages8
JournalComparative Biochemistry and Physiology Part - B: Biochemistry and Molecular Biology
Issue number4
StatePublished - Aug 1995
Externally publishedYes


  • Ascidiacea
  • Botryllus schlosseri
  • Complement
  • Immune-related protein
  • Invertebrate immunity
  • Short consensus repeats
  • TNF-α
  • Tunicates

ASJC Scopus subject areas

  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology
  • Biochemistry
  • Physiology


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