Fachbereich Veterinärmedizin



    Expression profiling, gene silencing and transcriptional networking of metzincin metalloproteases in the cattle tick, Rhipicephalus (Boophilus) microplus (2012)

    Zeitschriftenartikel / wissenschaftlicher Beitrag
    Barnard, Annette-Christi
    Nijhof, Ard M (WE 13)
    Gaspar, Anabella R M
    Neitz, Albert W H
    Jongejan, Frans
    Maritz-Olivier, Christine
    Veterinary Parasitology; 186(3/4) — S. 403–414
    ISSN: 0304-4017
    Pubmed: 22142943
    Institut für Parasitologie und Tropenveterinärmedizin

    Robert-von-Ostertag-Str. 7-13
    Gebäude 35, 22, 23
    14163 Berlin
    Tel.+49 30 838 62310 Fax.+49 30 838 62323

    Abstract / Zusammenfassung

    Tick proteins functioning in vital physiological processes such as blood meal uptake, digestion and reproduction are potential targets for anti-tick vaccines, since vaccination could inhibit these essential functions and ultimately affect tick survival. In this study we identified metzincin metalloproteases from Rhipicephalus microplus as potential vaccine candidates since they are implicated as essential to blood-cavity formation, bloodmeal digestion and reproduction in ixodid ticks. Eight transcripts encoding proteins that contain the characteristic metzincin zinc-binding motif HEXXHXXG/NXXH/D and a unique methionine containing "methionine-turn" were identified from native and in-house assembled R. microplus expressed sequence tag (EST) databases. These were representative of five reprolysin-like and three astacin-like metzincin metalloproteases. Reverse transcription-PCR analysis indicated that the reprolysins were most abundantly expressed in the salivary glands, whereas the astacins were most abundant in the midgut and ovaries. In vivo gene silencing was performed to assess a possible phenotype of these metalloproteases during adult female R. microplus blood feeding and reproduction. RNA interference (RNAi) against two of the reprolysins and one of the astacins significantly affected the average egg weight and oviposition rate. Evidently, this reverse genetic approach enabled the evaluation of the overall vital impact of tick proteins. Finally, integrated real time-PCR studies also revealed an extensive cross organ network between the R. microplus metzincin transcripts, supporting the use of a combinatorial metzincin-based anti- R. microplus vaccine.