title: Dynamics of Rickettsia-tick interactions: identification and characterization of differentially expressed mRNAs in uninfected and infected Dermacentor variabilis.
abstract: To begin to explore the molecular dynamics of rickettsial tick interaction, subtractive hybridization was used to screen mRNAs in Rickettsia montanensis-infected and uninfected Dermacentor variabilis. We isolated 30 cDNA fragments, 22 of which were up-regulated and eight were down-regulated in response to rickettsial infection. Based on a putative identity of 11 cDNA fragments with similarity to known protein families, the tick genetic factors have been assigned into three groups including, the tick immune response factors (alpha-2 macroglobulin and IgE-dependent histamine release factor), the receptor/adhesion molecules (the signal transducer and activator of transcription-1/3 protein inhibitor, the clathrin adaptor protein and tetraspanin) and the stress response proteins (aldose reductase, glutathione-S transferase, ferritin, nucleosome assembly protein and cyclin A protein). Density analyses of semiquantitative RT-PCR amplified products demonstrated differential expression for 18 of the 23 tested genetic factors, apparently representing a 78% agreement with results obtained by subtractive hybridization. Additionally, mRNA transcripts of 17 of the 23 tested genetic factors were amplified from tick haemocytes/circulatory cells demonstrating that their expression is not restricted to the ovaries and suggesting a potential involvement in the immune response.
authors.affiliation: Department of Microbiology, School of Medicine, University of Maryland, 655 West Baltimore Street, Baltimore, MD 21201, USA. amvle001@umaryland.edu
authors.forename: A
authors.initials: A
authors.lastname: Mulenga
authors.forename: K R
authors.initials: KR
authors.lastname: Macaluso
authors.forename: J A
authors.initials: JA
authors.lastname: Simser
authors.forename: A F
authors.initials: AF
authors.lastname: Azad
mesh_terms: D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003870:Dermacentor / Q000235:genetics / Q000382:microbiology*; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012281:Rickettsia / Q000235:genetics / Q000254:growth & development*; D012282:Rickettsia Infections / Q000382:microbiology
chemical_list: D012333:RNA, Messenger