Development of a cDNA microarray for the measurement of gene expression in the sheep scab mite Psoroptes ovis.
BACKGROUND
Sheep scab is caused by the ectoparasitic mite Psoroptes ovis which initiates a profound cutaneous inflammatory response, leading to the development of the skin lesions which are characteristic of the disease. Existing control strategies rely upon injectable endectocides and acaricidal dips but concerns over residues, eco-toxicity and the development of acaricide resistance limit the sustainability of this approach. In order to identify alternative means of disease control, a deeper understanding of both the parasite and its interaction with the host are required.


METHODS
Herein we describe the development and utilisation of an annotated P. ovis cDNA microarray containing 3,456 elements for the measurement of gene expression in this economically important ectoparasite. The array consists of 981 P. ovis EST sequences printed in triplicate along with 513 control elements. Array performance was validated through the analysis of gene expression differences between fed and starved P. ovis mites.


RESULTS
Sequences represented on the array include homologues of major house dust mite allergens and tick salivary proteins, along with factors potentially involved in mite reproduction and xenobiotic metabolism. In order to validate the performance of this unique resource under biological conditions we used the array to analyse gene expression differences between fed and starved P. ovis mites. These analyses identified a number of house dust mite allergen homologues up-regulated in fed mites and P. ovis transcripts involved in stress responses, autophagy and chemosensory perception up-regulated in starved mites.


CONCLUSIONS
The P. ovis cDNA microarray described here has been shown to be both robust and reproducible and will enable future studies to analyse gene expression in this important ectoparasite.
Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian EH26 0PZ, UK. stewart.burgess@moredun.ac.uk
Stewart T G
ST
Burgess
Alison
A
Downing
Craig A
CA
Watkins
Edward J
EJ
Marr
Alasdair J
AJ
Nisbet
Fiona
F
Kenyon
Carol
C
McNair
John F
JF
Huntley
D000818:Animals; D018076:DNA, Complementary / Q000235:genetics; D020224:Expressed Sequence Tags; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000235:genetics*; D015723:Gene Library; D054884:Host-Pathogen Interactions; D008297:Male; D008924:Mite Infestations / Q000469:parasitology / Q000662:veterinary*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D040042:Psoroptidae / Q000235:genetics* / Q000502:physiology; D011786:Quality Control; D012313:RNA / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D017422:Sequence Analysis, DNA; D012756:Sheep; D012757:Sheep Diseases / Q000469:parasitology*
D018076:DNA, Complementary; D012313:RNA