title: Chaperonin contributes to cold hardiness of the onion maggot Delia antiqua through repression of depolymerization of actin at low temperatures.
abstract: Winter-diapause and cold-acclimated non-diapause pupae of the onion maggot, Delia antiqua (Diptera: Anthomyiidae), show strong cold hardiness. To obtain insights into the mechanisms involved in the enhancement of cold hardiness, we investigated the expression patterns of genes encoding subunits of chaperonin (CCT) and the morphology of actin, a substrate of CCT, at low temperatures. Quantitative real-time PCR analyses showed the mRNA levels of CCT subunits in pupal tissues to be highly correlated with the cold hardiness of the pupae. While actin in the Malpighian tubules of non-cold-hardy pupae showed extensive depolymerization after a cold treatment, actin in the same tissue of cold-hardy pupae was not depolymerized. Damage to cell membranes became apparent after the depolymerization of actin. Moreover, administration of Latrunculin B, an inhibitor of actin polymerization, to the larvae markedly decreased the cold hardiness of the pupae obtained. These findings suggest that CCT contributes to the cold hardiness of D. antiqua through the repression of depolymerization of actin at low temperatures.
authors.affiliation: Laboratory of Applied Entomology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Kayukawa
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ishikawa
mesh_terms: D000064:Acclimatization / Q000187:drug effects; D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D018833:Chaperonins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D003080:Cold Temperature; D004175:Diptera / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D008317:Malpighian Tubules / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D019697:Onions / Q000469:parasitology*; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011679:Pupa / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D053778:Thiazolidines / Q000494:pharmacology
chemical_list: D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D021122:Protein Subunits; D012333:RNA, Messenger; D053778:Thiazolidines; D018833:Chaperonins; C037068:latrunculin B