Four serine proteinase inhibitors (serpin) from the brown ear tick, Rhiphicephalus appendiculatus; cDNA cloning and preliminary characterization

Insect Biochem Mol Biol. 2003 Feb;33(2):267-76. doi: 10.1016/s0965-1748(02)00240-0.


While development of an anti-Boophilus microplus vaccine is advanced and practical, work on other economically important ticks such as Rhipicephalus appendiculatus is still in its infancy. Guess PCR primers, designed from a consensus amino acid sequence (NAVYKFG) motif were used with rapid amplification of cDNA ends (RACE) to clone four cDNAs encoding serine proteinase inhibitors (serpin) from the brown ear tick Rhipicephalus appendiculatus. The four genes designated as R. appendiculatus serpin (RAS) -1 to -4 encode polypeptides of 378, 380, 398 and 486 amino acids long, respectively. Sequence comparison of RAS-1 to -4 predicted amino acid sequences to the serpin-like hypothetical protein from Ixodes ricinus (Leboulle et al., 2002) revealed closer structural similarities among tick serpins. Expression analysis by RT-PCR showed that RAS-1 to -4 are expressed in other tick organs in addition to salivary glands and midguts. Except for RAS-3 whose expression level appears to be equivalent in all tick organs, RAS-1, -2 and -4 are predominantly expressed in the salivary glands. We have discussed our findings with reference to development of vaccines against R. appendiculatus.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • DNA Primers
  • DNA, Complementary / genetics
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / isolation & purification
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Serine Proteinase Inhibitors / genetics
  • Serine Proteinase Inhibitors / isolation & purification*
  • Serpins / genetics
  • Serpins / isolation & purification*
  • Ticks* / genetics*


  • DNA Primers
  • DNA, Complementary
  • Recombinant Proteins
  • Serine Proteinase Inhibitors
  • Serpins