Molecular cloning, expression and isolation of ferritins from two tick species--Ornithodoros moubata and Ixodes ricinus.
Genes encoding ferritins were isolated and cloned from cDNA libraries of hard tick Ixodes ricinus and soft tick Ornithodoros moubata. Both tick ferritins are composed of 172 amino-acid residues and their calculated mass is 19,667.2 Da and 19,974.5 Da for I. ricinus and O. moubata, respectively. The sequences of both proteins are closely related to each other as well as to the ferritin from another tick species Dermacentor variabilis (>84% similarity). The proteins contain the conserved motifs for ferroxidase center typical for heavy chains of vertebrate ferritins. The stem-loop structure of a putative iron responsive element was found in the 5' untranslated region of ferritin mRNA of both ticks. Antibodies against fusion ferritin from O. moubata were raised in a rabbit and used to monitor the purification of a small amount of ferritins from both tick species. The authenticity of ferritin purified from O. moubata was confirmed by mass-fingerprinting analysis. In the native state, the tick ferritins are apparently larger (~500 kDa) than horse spleen ferritin (440 kDa). On SDS-PAGE tick ferritins migrate as a single band of about 21 kDa. These results suggest that tick ferritins are homo-oligomers of 24 identical subunits of heavy-chain type. The Northern blot analysis revealed that O. moubata ferritin mRNA level is likely not up-regulated after ingestion of a blood meal.
Kopácek
Petr
P
Institute of Parasitology, Academy of Sciences of the Czech Republic and Faculty of Biological Sciences, University of South Bohemia, Branisovská 31, 370 05, Ceské Budejovice, Czech Republic. kopajz@paru.cas.cz
Zdychová
Jana
J
Yoshiga
Toyoshi
T
Weise
Christoph
C
Rudenko
Natasha
N
Law
John H
JH
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004591:Electrophoresis, Polyacrylamide Gel; D005293:Ferritins / Q000235:genetics*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013987:Ticks / Q000235:genetics*
D018076:DNA, Complementary; D012333:RNA, Messenger; D005293:Ferritins