title: Upregulation of two actin genes and redistribution of actin during diapause and cold stress in the northern house mosquito, Culex pipiens.
abstract: Two actin genes cloned from Culex pipiens L. are upregulated during adult diapause. Though actins 1 and 2 were expressed throughout diapause, both genes were most highly expressed early in diapause. These changes in gene expression were accompanied by a conspicuous redistribution of polymerized actin that was most pronounced in the midguts of diapausing mosquitoes that were exposed to low temperature. In nondiapausing mosquitoes reared at 25 degrees C and in diapausing mosquitoes reared at 18 degrees C, polymerized actin was clustered at high concentrations at the intersections of the muscle fibers that form the midgut musculature. When adults 7-10 days post-eclosion were exposed to low temperature (-5 degrees C for 12 h), the polymerized actin was evenly distributed along the muscle fibers in both nondiapausing and diapausing mosquitoes. Exposure of older adults (1 month post-eclosion) to low temperature (-5 degrees C for 12 h) elicited an even greater distribution of polymerized actin, an effect that was especially pronounced in diapausing mosquitoes. These changes in gene expression and actin distribution suggest a role for actins in enhancing survival of diapausing adults during the low temperatures of winter by fortification of the cytoskeleton.
authors.affiliation: Department of Entomology, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Mijung
authors.initials: M
authors.lastname: Kim
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Robich
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Rinehart
authors.forename: David L
authors.initials: DL
authors.lastname: Denlinger
mesh_terms: D000199:Actins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D015152:Blotting, Northern / Q000662:veterinary; D003001:Cloning, Molecular; D003080:Cold Temperature; D003465:Culex / Q000235:genetics / Q000502:physiology*; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D019476:Insect Proteins / Q000737:chemistry; D007422:Intestines / Q000502:physiology; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D015854:Up-Regulation
chemical_list: D000199:Actins; D017931:DNA Primers; D019476:Insect Proteins