A salivary cystatin, HlSC-1, from the ixodid tick Haemaphysalis longicornis play roles in the blood-feeding processes.
Ticks feed exclusively on blood to obtain their nutrients, but the gene products that mediate blood-sucking processes in ticks are still unknown. We report here the molecular characterization and possible biological function of a cysteine protease inhibitor (HlSC-1) identified in the salivary gland of the ixodid tick Haemaphysalis longicornis. The HlSC-1 cDNA contains 423 bp that code for 140 amino acids with a predictable molecular weight of 12 kDa. The recombinant HlSC-1 expressed in Escherichia coli was shown to inhibit the activity of papain and cathepsin L, while cathepsin B activity was unaffected. Immunolocalization studies detected the endogenous enzyme in the salivary gland type II acini of an adult tick. Furthermore, quantitative RT-PCR analysis showed that the expression of HlSC-1 transcripts was associated with blood-feeding processes and was highly up-regulated in the early phase of feeding. Our results strongly suggest that HlSC-1 may play pivotal roles in the blood-feeding processes.
Laboratory of Parasitic Diseases, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan.
Kayoko
K
Yamaji
Naotoshi
N
Tsuji
Takeharu
T
Miyoshi
M Khyrul
MK
Islam
Takeshi
T
Hatta
M Abdul
MA
Alim
M
M
Anisuzzaman
Shiro
S
Kushibiki
Kozo
K
Fujisaki
D000595:Amino Acid Sequence; D000818:Animals; D001769:Blood; D002401:Cathepsin B / Q000037:antagonists & inhibitors; D056668:Cathepsin L / Q000037:antagonists & inhibitors; D003001:Cloning, Molecular; D004435:Eating / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D020869:Gene Expression Profiling; D019476:Insect Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D026863:Ixodidae / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010206:Papain / Q000037:antagonists & inhibitors; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055333:Salivary Cystatins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D012469:Salivary Glands / Q000737:chemistry; D016415:Sequence Alignment; D015854:Up-Regulation
D019476:Insect Proteins; D055333:Salivary Cystatins; D002401:Cathepsin B; D056668:Cathepsin L; D010206:Papain