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Hemalin, a thrombin inhibitor isolated from a midgut cDNA library from the hard tick Haemaphysalis longicornis.
- Source :
-
Journal of insect physiology [J Insect Physiol] 2009 Feb; Vol. 55 (2), pp. 164-73. Date of Electronic Publication: 2008 Dec 25. - Publication Year :
- 2009
-
Abstract
- A full-length sequence of a thrombin inhibitor (designated as hemalin) from the midgut of parthenogenetic Haemaphysalis longicornis has been identified. Sequence analysis shows that this gene belongs to the Kunitz-type family, containing two Kunitz domains with high homology to boophilin, the thrombin inhibitor from Rhipicephalus (Boophilus) microplus. The recombinant protein expressed in insect cells delayed bovine plasma clotting time and inhibited both thrombin-induced fibrinogen clotting and platelet aggregation. A 20-kDa protein was detected from the midgut lysate with antiserum against recombinant hemalin. The gene is expressed at all stages of the tick except for the egg stage, and hemalin mRNA mainly in the midgut of the female adult tick. Real-time PCR analysis shows that this gene has a distinctly high expression level in the rapid bloodsucking period of the larvae, nymphs, and adults. Disruption of the hemalin gene by RNA interference led to a 2-day extension of the tick blood feeding period, and 27.7% of the RNA-treated ticks did not successfully complete the blood feeding. These findings indicate that the newly identified thrombin inhibitor from the midgut of H. longicornis might play an important role in tick blood feeding.
- Subjects :
- Amino Acid Sequence
Animals
Base Sequence
Cell Line
DNA Primers genetics
Digestive System chemistry
Gene Library
Immunoblotting
Intercellular Signaling Peptides and Proteins
Molecular Sequence Data
Peptides metabolism
Platelet Aggregation drug effects
RNA Interference
Sequence Alignment
Sequence Analysis, DNA
Ixodidae genetics
Peptides genetics
Thrombin antagonists & inhibitors
Subjects
Details
- Language :
- English
- ISSN :
- 0022-1910
- Volume :
- 55
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Journal of insect physiology
- Publication Type :
- Academic Journal
- Accession number :
- 19061894
- Full Text :
- https://doi.org/10.1016/j.jinsphys.2008.11.004