Molecular characterization of a troponin I-like protein from the hard tickHaemaphysalis longicornis

A cDNA expression library prepared from mRNA of Haemaphysalis longicornis ( H. longicornis) was screened with a H. longicornis-infested rabbit serum. A cDNA encoding 27/30 kDa proteins was cloned and designated P27/30 gene. Th e predicted amino acid sequence of the P27/30 gene shows a rather high homo logy (58% amino acid identities and 11% amino acid similarity) with Drosoph ila melanogaster troponin I clone E2. H. longicornis P27/30 possesses amino acid sequence of actin-binding domains of troponin I at the amino acid res idues 128-148, suggesting that H. longicornis P27/30 is a troponin I-like p rotein. By immunoblot analysis, mouse anti-recombinant P27/30 serum reacted with major constituent protein bands in extracts of adult ticks, and also immunoreacted with muscle, cuticle, gut, and salivary gland in H. longicorn is ticks. Moreover, immunohistochemistry using the anti-P27/30 serum showed a strong reactivity in muscle, suggesting that native P27/30 is expressed abundantly in that tissue. (C) 2001 Elsevier Science Ltd. All rights reserv ed.