title: A protective role of HSP90 chaperone in gamma-irradiated Arabidopsis thaliana seeds.
abstract: The heat shock protein 90 (HSP90) is required for the maturation and conformational regulation of many regulatory proteins affecting morphogenetic pathways and stress tolerance. The purpose of this work is to disclose a role of HSP90 in radioresistance of seeds. Arabidopsis thaliana (Ler) seeds were exposed to γ-ray irradiation with doses of 0.1-1 kGy using (60)Co source to obtain a viable but polymorphic material. A comet assay of the seeds showed a dose-dependent increase in DNA damage. Phenotypic consequences of irradiation included growth stimulation at doses of 0.1-0.25 kGy and negative growth effects at doses from 0.5 kGy and beyond, along with increasing heterogeneity of seedling growth rate and phenotype. The frequencies of abnormal phenotypes were highly correlated with the degree of DNA damage in seeds. Treatment of seeds with geldanamycin (GDA), an inhibitor of HSP90, stimulated the seedling growth at all radiation doses and, at the same time, enhanced the growth rate and morphological diversity. It was also found that HSP70 induction by γ-rays was increased following GDA treatment (shown at 1 kGy). We suppose that the GDA-induced HSP70 can be involved in elimination of detrimental radiation effects that ultimately results in growth stimulation. On the other hand, the increase in phenotypic variation, when HSP90 function was impaired, confirms the supposition that the chaperone may control the concealment of cryptic genetic alterations and the developmental stability. In general, these results demonstrate that HSP90 may interface the stress response and phenotypic expression of genetic alterations induced by irradiation.
authors.affiliation: Department of Cell Biology and Anatomy, Institute of Botany, NAS of Ukraine, Tereshchenkivska str. 2, 01601 Kyiv, Ukraine. Electronic address: liudmyla.kozeko@gmail.com.
authors.forename: Liudmyla
authors.initials: L
authors.lastname: Kozeko
authors.affiliation: Department of Cell Biology and Anatomy, Institute of Botany, NAS of Ukraine, Tereshchenkivska str. 2, 01601 Kyiv, Ukraine. Electronic address: atalalaev@yahoo.com.
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Talalaiev
authors.affiliation: Laboratory of radiation technology, Institute of Physics, NAS of Ukraine, Nauky av. 46, 03028, Kyiv, Ukraine. Electronic address: neimash@gmail.com.
authors.forename: Volodymyr
authors.initials: V
authors.lastname: Neimash
authors.affiliation: Laboratory of radiation technology, Institute of Physics, NAS of Ukraine, Nauky av. 46, 03028, Kyiv, Ukraine. Electronic address: pvyu@i.ua.
authors.forename: Vasyl
authors.initials: V
authors.lastname: Povarchuk
mesh_terms: D017360:Arabidopsis / Q000254:growth & development / Q000528:radiation effects*; D016227:Benzoquinones / Q000494:pharmacology; D004249:DNA Damage / Q000528:radiation effects*; D005720:Gamma Rays / Q000009:adverse effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D018525:Germination / Q000528:radiation effects*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047029:Lactams, Macrocyclic / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000494:pharmacology; D011836:Radiation Tolerance / Q000502:physiology; D036226:Seedlings / Q000254:growth & development* / Q000528:radiation effects; D012639:Seeds / Q000254:growth & development / Q000528:radiation effects*
chemical_list: D016227:Benzoquinones; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D011505:Protein-Tyrosine Kinases; C001277:geldanamycin
keywords: Arabidopsis thaliana; Gamma irradiation; Geldanamycin; HSP70; HSP90 inhibition; Phenotypic diversity