CLONING AND SEQUENCING OF PUTATIVE CALRETICULIN COMPLEMENTARY DNAs FROM FOUR HARD TICK SPECIES

• Published in: The Journal of parasitology Vol. 90; no. 1; pp. 73 - 78
• Main Authors: Xu, Guang, Fang, Quentin Q, Keirans, James E, Durden, Lance A
• Format: Journal Article
• Language: English
• Published: United States American Society of Parasitologists 01.02.2004
• Subjects: Amino Acid Sequence; amino acid sequences; Amino acids; Animals; Average total cost; Base Sequence; Biological taxonomies; calreticulin; Calreticulin - chemistry; Calreticulin - genetics; Cloning, Molecular; Complementary DNA; Conserved Sequence; Cysteine - chemistry; Dermacentor - chemistry; Dermacentor - classification; Dermacentor - genetics; Dermacentor variabilis; DNA, Complementary - chemistry; Dogs; gene expression; Gene Expression Regulation; Generally accepted auditing standards; GENETICS-EVOLUTION; Haemaphysalis longicornis; Ixodes - chemistry; Ixodes - classification; Ixodes - genetics; Ixodes scapularis; Ixodidae - chemistry; Ixodidae - classification; Ixodidae - genetics; Molecular Sequence Data; nucleotide sequences; Open Reading Frames - genetics; Parasitology; Phylogenetics; Phylogeny; Polymerase chain reaction; Protein Sorting Signals - genetics; Random Amplified Polymorphic DNA Technique; Reverse Transcriptase Polymerase Chain Reaction; Rhipicephalus sanguineus; sequence analysis; Ticks
• DOI: 10.1645/GE-157R
• ISSN: 0022-3395

Calreticulin (CRT) is a calcium-binding protein and has many functions in eukaryotic cells. CRT is possibly involved in parasite host immune system evasion. To better understand the molecular basis of CRT in ticks, we cloned and sequenced 4 full-length complementary DNAs (cDNAs) from the hard tick species, Dermacentor variabilis, Haemaphysalis longicornis, Ixodes scapularis, and Rhipicephalus sanguineus, using the technique of rapid amplification of cDNA ends. The deduced amino acid sequences share high identities (between 77 and 98%) with 3 known tick CRT sequences. The major characteristics of known CRTs are observed in all 4 of our deduced tick CRTs. These include 3 major domains, a signal peptide sequence at the beginning of the coding region, 2 triplets of conserved regions, cysteine sites providing disulfide bridges for N-terminal folding, and a nuclear localization signal. Remarkably, the replacement of the endoplasmic reticulum retention signal KDEL by HEEL, which is believed to be associated with secretion of CRT into the host during feeding and was previously recorded only in 2 ticks and a hookworm, is also present in all 4 of our tick putative CRTs. In addition, the CRT gene is potentially useful for tick phylogenetic reconstruction.