Molecular Cloning of Two Rhipicephalus haemaphysaloides haemaphysaloides Cathepsin L-like Cysteine Proteinase Gene
镰形扇头蜱两个组织蛋白酶L-样半胱氨酸蛋白酶新基因的克隆与序列分析

Ticks are obligate ectoparasites and vectors of arboviruses,vickettsiate, spiroc hetes and parasitil protozoa of humans and domestic animals. Immunological prote ction of mammalian hosts against tick infestation has been proposed as the most sustainable alternative tick control method to the current use of acaricides. Th e success of this method is dependent on the identification of key molecules for use as tick vaccine antigens. Proteolytic enzymes are involved in a wide range of cellular processes, thus they can be considered as good target antigens for a tick vaccine. In the present study, we used rapid amplification of cDNA ends pr otocol and primers that were designed based on the consensus amino acid motifs f lanking present in all papain-like cysteine proteinases, to amplify, sequence a nd characterize two Rhipicephalus haemaphysaloides haemaphysaloides cathepsi n L-like cysteine proteinases, named as cysA and cysB. The full length of cysA is 1168bp, encoding a 332 amino acid residue polypeptide with 36 33 kD predicted molecular mass; the full length of cysB is 1153bp, encoding a 335 a mino acid residue polypeptide with 37 56kD predicted molecular mass. The consen sus amino acid motifs flanking presence in both deduced amino acid sequences. An d both genes show high sequence homology to other tick cathepsin L-like cystein e proteinase, so they were identified as members of the cysteine proteinase gene family. Expression analysis by RT-PCR revealed that cysA and cysB were expressed differently in different periods of tick development.