Salivary gland transcriptome analysis during Plasmodium infection in malaria vector Anopheles stephensi.
BACKGROUND
Understanding the tissue-specific molecular cross-talk mechanism during the mosquito-parasite interaction is of prime importance in the design of new strategies for malaria control. Because mosquito salivary glands are the final destination for the parasite maturation and transmission of vector-borne diseases, identification and characterization of salivary genes and their products are equally important in order to access their effect on the infectivity of the parasite. During the last five years there have been several studies on the sialomes of Anopheles mosquitoes, however very limited information is available on the changes in the salivary gland transcriptome in the presence of Plasmodium, and this information is limited to the mosquito Anopheles gambiae.


METHODS
In this study we aimed to explore and identify parasite-induced transcripts from the salivary glands of Anopheles stephensi, using a subtractive hybridization protocol.


RESULTS
Ninety-four percent of expressed sequence tags (ESTs) showed close homology to previously known families of mosquito salivary gland secretary proteins, representing the induced expression of alternative splicing and/or additional new members of the protein family. The remaining 6% of ESTs did not yield significant homology to any known proteins in the non-redundant database and thus may represent a class of unknown/novel salivary proteins. Primary analysis of the ESTs also revealed identification of several novel immune-related transcripts, including defensin and cecropins, probably involved in counter-activation of the antagonistic defense system. A comprehensive description of each family of proteins has been discussed in relation to the tissue-specific mosquito-parasite interaction.


CONCLUSIONS
This is the first report on the identification of new putative salivary genes, presumably activated during parasite infection.
Dixit
Rajnikant
R
Molecular Biology Unit, National Center for Cell Science, Ganeshkhind, Pune, India. dixit2k@yahoo.com
Sharma
Arun
A
Mourya
Devendra T
DT
Kamaraju
Raghavendra
R
Patole
Millind S
MS
Shouche
Yogesh S
YS
D000595:Amino Acid Sequence; D000818:Animals; D000852:Anopheles / Q000145:classification / Q000469:parasitology*; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D015723:Gene Library; D006790:Host-Parasite Interactions; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007303:Insect Vectors / Q000469:parasitology; D008288:Malaria / Q000469:parasitology; D051379:Mice; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization / Q000379:methods; D010962:Plasmodium berghei / Q000472:pathogenicity*; D012469:Salivary Glands / Q000378:metabolism / Q000469:parasitology; D012471:Salivary Proteins and Peptides / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA
D019476:Insect Proteins; D012471:Salivary Proteins and Peptides