title: Stress response in tardigrades: differential gene expression of molecular chaperones.
abstract: Semi-terrestrial tardigrades exhibit a remarkable tolerance to desiccation by entering a state called anhydrobiosis. In this state, they show a strong resistance against several kinds of physical extremes. Because of the probable importance of stress proteins during the phases of dehydration and rehydration, the relative abundance of transcripts coding for two alpha-crystallin heat-shock proteins (Mt-sHsp17.2 and Mt-sHsp19.5), as well for the heat-shock proteins Mt-sHsp10, Mt-Hsp60, Mt-Hsp70 and Mt-Hsp90, were analysed in active and anhydrobiotic tardigrades of the species Milnesium tardigradum. They were also analysed in the transitional stage (I) of dehydration, the transitional stage (II) of rehydration and in heat-shocked specimens. A variable pattern of expression was detected, with most candidates being downregulated. Gene transcripts of one Mt-hsp70 isoform in the transitional stage I and Mt-hsp90 in the anhydrobiotic stage were significantly upregulated. A high gene expression (778.6-fold) was found for the small alpha-crystallin heat-shock protein gene Mt-sHsp17.2 after heat shock. We discuss the limited role of the stress-gene expression in the transitional stages between the active and anhydrobiotic tardigrades and other mechanisms which allow tardigrades to survive desiccation.
authors: Zoology, Biological Institute, Universität Stuttgart, Pfaffenwaldring 57, 70569, Stuttgart, Germany.
authors: Andy
authors: A
authors: Reuner
authors: Steffen
authors: S
authors: Hengherr
authors: Brahim
authors: B
authors: Mali
authors: Frank
authors: F
authors: Förster
authors: Detlev
authors: D
authors: Arndt
authors: Richard
authors: R
authors: Reinhardt
authors: Thomas
authors: T
authors: Dandekar
authors: Marcus
authors: M
authors: Frohme
authors: Franz
authors: F
authors: Brümmer
authors: Ralph O
authors: RO
authors: Schill
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003681:Dehydration; D015536:Down-Regulation; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D007448:Invertebrates / Q000378:metabolism*; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D038201:alpha-Crystallins / Q000235:genetics / Q000378:metabolism
chemical_list: D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D038201:alpha-Crystallins