title: Differential transcription of the major antigenic protein 1 multigene family of Ehrlichia ruminantium in Amblyomma variegatum ticks.
abstract: The rickettsial pathogen Ehrlichia ruminantium causes heartwater in ruminants and is transmitted by ticks of the genus Amblyomma. The map1 gene, encoding the major surface protein MAP1, is a member of a multigene family containing 16 paralogs. In order to investigate differential transcription of genes of the map1 multigene family in vivo in unfed and feeding ticks, RNA was extracted from midguts and salivary glands of E. ruminantium-infected adult female Amblyomma variegatum ticks and analysed by RT-PCR using MAP1 paralog-specific primers. In unfed ticks, only transcripts from the map1-1 gene were observed in midguts and no transcripts were detected in salivary glands. In feeding ticks, map1-1 transcripts were more abundant in midguts whereas high levels of map1 transcripts were observed in salivary glands. Our results show that differential transcription of genes of the E. ruminantium map1 cluster occurs in vivo in different tissues of infected ticks before and during transmission feeding, indicating that this multigene family may be involved in functions of biological relevance in different stages of the life cycle of E. ruminantium.
authors.affiliation: Utrecht Centre for Tick-borne Diseases, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands. m.postigo@vet.uu.nl
authors.forename: M
authors.initials: M
authors.lastname: Postigo
authors.forename: A
authors.initials: A
authors.lastname: Taoufik
authors.forename: L
authors.initials: L
authors.lastname: Bell-Sakyi
authors.forename: E
authors.initials: E
authors.lastname: de Vries
authors.forename: W I
authors.initials: WI
authors.lastname: Morrison
authors.forename: F
authors.initials: F
authors.lastname: Jongejan
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D002478:Cells, Cultured; D017931:DNA Primers; D004269:DNA, Bacterial / Q000302:isolation & purification; D016995:Ehrlichia ruminantium / Q000235:genetics*; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D006357:Heartwater Disease / Q000635:transmission*; D008969:Molecular Sequence Data; D005810:Multigene Family; D012329:RNA, Bacterial / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D012469:Salivary Glands / Q000382:microbiology; D012756:Sheep; D012757:Sheep Diseases / Q000635:transmission; D013987:Ticks / Q000382:microbiology*; D014158:Transcription, Genetic
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D012329:RNA, Bacterial; C086402:major antigenic protein 1, Cowdria ruminantium