ARS | Publication request: Diapause-specific gene expression in the northern house mosquito, Culex pipiens L., identified by suppressive subtractive hybridization

Submitted to: Journal of Insect Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 4, 2006
Publication Date: March 1, 2007
Citation: Robich, R.M., Rinehart, J.P., Kitchen, L.J., Denlinger, D.L. 2007. Diapause-specific gene expression in the northern house mosquito, Culex pipiens L., identified by suppressive subtractive hybridization. Journal of Insect Physiology. 53(3):235-245.

Interpretive Summary: Winter poses a major challenge for insects. To be successful in environments with distinct seasons, insects must grow and reproduce only for a few months during the summer and then survive the remainder of the year without feeding, while dealing with the stresses that winter brings to them. Most insects survive winter by entering diapause, a state that is characterized by, among other things, an increase in stress tolerance. In this study, we used molecular techniques to determine what genes are present in higher levels and what genes are present in lower levels during diapause in the northern house mosquito, Culex pipiens. The identification of these genes has given us an increased understanding of how diapause works in this important insect species.

Technical Abstract: In this study we probe the molecular events underpinning diapause observed in overwintering females of Culex pipiens. Using suppressive subtractive hybridization (SSH) we have identified 40 genes that are either upregulated or downregulated during this seasonal period of dormancy. Northern blot hybridizations have confirmed the expression of 32 of our SSH clones, including six genes that are upregulated specifically in early diapause, 17 that are upregulated in late diapause, and two upregulated throughout diapause. In addition, two genes are diapause downregulated and five remain unchanged during diapause. These genes can be categorized into eight functional groups: genes with regulatory functions, metabolically-related genes, those involved in food utilization, stress response genes, cytoskeletal genes, ribosomal genes, transposable elements, and genes with unknown functions.