title: Characterization of six small HSP genes from Chironomus riparius (Diptera, Chironomidae): Differential expression under conditions of normal growth and heat-induced stress.
abstract: Small heat shock proteins (sHSPs) comprise the most numerous, structurally diverse, and functionally uncharacterized family of heat shock proteins. Several Hsp genes (Hsp 90, 70, 40, and 27) from the insect Chironomus riparius are widely used in aquatic toxicology as biomarkers for environmental toxins. Here, we conducted a comparative study and characterized secondary structure of the six newly identified sHsp genes Hsp17, Hsp21, Hsp22, Hsp23, Hsp24, and Hsp34. A characteristic α-crystallin domain is predicted in all the new proteins. Phylogenetic analysis suggests a strong relation to other sHSPs from insects and interesting evidence regarding evolutionary origin and duplication events. Comparative analysis of transcription profiles for Hsp27, Hsp70, and the six newly identified genes revealed that Hsp17, Hsp21, and Hsp22 are constitutively expressed under normal conditions, while under two different heat shock conditions these genes are either not activated or are even repressed (Hsp22). In contrast, Hsp23, Hsp24, and Hsp34 are significantly activated along with Hsp27 and Hsp70 during heat stress. These results strongly suggest functional differentiation within the small HSP subfamily and provide new data to help understand the coping mechanisms induced by stressful environmental stimuli.
authors.affiliation: Grupo de Biología y Toxicología Ambiental, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, UNED, Senda del Rey 9, 28040 Madrid, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Martín-Folgar
authors.affiliation: Departamento de Ciencias y Técnicas Fisicoquímicas, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, UNED, Senda del Rey 9, 28040 Madrid, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: de la Fuente
authors.affiliation: Grupo de Biología y Toxicología Ambiental, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, UNED, Senda del Rey 9, 28040 Madrid, Spain.
authors.forename: Gloria
authors.initials: G
authors.lastname: Morcillo
authors.affiliation: Grupo de Biología y Toxicología Ambiental, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, UNED, Senda del Rey 9, 28040 Madrid, Spain. Electronic address: jlmartinez@ccia.uned.es.
authors.forename: José-Luis
authors.initials: JL
authors.lastname: Martínez-Guitarte
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002683:Chironomidae / Q000235:genetics* / Q000254:growth & development; D020869:Gene Expression Profiling / Q000379:methods*; D018507:Gene Expression Regulation, Developmental; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics*; D018869:Heat-Shock Response / Q000235:genetics; D006358:Hot Temperature; D019476:Insect Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D020033:Protein Isoforms / Q000737:chemistry / Q000145:classification / Q000235:genetics; D017433:Protein Structure, Secondary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological / Q000235:genetics
chemical_list: D006360:Heat-Shock Proteins; D019476:Insect Proteins; D020033:Protein Isoforms
keywords: Heat shock; sHSPs; α-Crystallin