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Heat shock gene promoters represent a highly conserved and universal system for the rapid induction of transcription after various stressful stimuli. We chose pairs of mammalian and insect species that significantly differ in their thermoresistance and constitutive levels of Hsp70 to compare hsp promoter strength under normal conditions and after heat shock (HS). The first pair includes the HSPA1 gene promoter of camel (Camelus dromedarius) and humans. It was demonstrated that the camel HSPA1A and HSPA1L promoters function normally in vitro in human cell cultures and exceed the strength of orthologous human promoters under basal conditions. We used the same in vitro assay for Drosophila melanogaster Schneider-2 (S2) cells to compare the activity of the hsp70 and hsp83 promoters of the second species pair represented by Diptera, i.e., Stratiomys singularior and D. melanogaster, which dramatically differ in thermoresistance and the pattern of Hsp70 accumulation. Promoter strength was also monitored in vivo in D. melanogaster strains transformed with constructs containing the S. singularior hsp70 ORF driven either by its own promoter or an orthologous promoter from the D. melanogaster hsp70Aa gene. Analysis revealed low S. singularior hsp70 promoter activity in vitro and in vivo under basal conditions and after HS in comparison with the endogenous promoter in D. melanogaster cells, which correlates with the absence of canonical GAGA elements in the promoters of the former species. Indeed, the insertion of GAGA elements into the S. singularior hsp70 regulatory region resulted in a dramatic increase in promoter activity in vitro but only modestly enhanced the promoter strength in the larvae of the transformed strains. In contrast with hsp70 promoters, hsp83 promoters from both of the studied Diptera species demonstrated high conservation and universality.

Heat shock proteins (Hsp) provide cellular and whole body adaptation of animals to various adverse environmental conditions. Hsp70 is apparently the major player underlying biological adaptation in all organisms studied so far. In all animals the regulatory regions of studied heat shock genes include several conservative promoter elements HSEs (heat shock elements) that are necessary for binding of heat shock transcription factor (HSF). The promoter regions of hsp70 genes are extremely conserved and, hence, it was generally accepted that they are universal and can operate in species belonging to different phyla. In the present work we performed the comparative analysis which revealed characteristic differences in the hsp 70 promoters of two Diptera species: Drosophila melanogaster and highly thermotolerance soldier fly Stratiomys singularior. We measured promoters activity in D. melanogaster cell culture exploring in vitro luciferase reporter assay. The analysis demonstrated significantly higher strength ofD. melanogaster promoters in spite of the fact that comparable numbers of HSEs are present in both species. These drastic differences in the promoter strength are probably due to absence of GAF-binding sites, which are necessary for efficient functioning of D. melanogaster hsp70 promoters. In contrast, comparison of hsp83 promoters isolated from these two species does not show significant differences. Our results demonstrate existence of different evolutionary trends in the regulation of the hsp70 expression even within the same order (Diptera).

The heat shock proteins belonging to the Hsp90 family (Hsp83 in Diptera) play a crucial role in the protection of cells due to their chaperoning functions. We sequenced hsp90 genes from three species of the family Stratiomyidae (Diptera) living in thermally different habitats and characterized by extraordinarily high thermotolerance. The sequence variation and structure of the hsp90 family genes were compared with previously described features of hsp70 copies isolated from the same species. Two functional hsp83 genes were found in the species studied, that are arranged in tandem orientation at least in one of them. This organization was not previously described. Stratiomyidae hsp83 genes share a high level of identity with hsp83 of Drosophila, and the deduced protein possesses five conserved amino acid sequence motifs characteristic of the Hsp90 family as well as the C-terminus MEEVD sequence characteristic of the cytosolic isoform. A comparison of the hsp83 promoters of two Stratiomyidae species from thermally contrasting habitats demonstrated that while both species contain canonical heat shock elements in the same position, only one of the species contains functional GAF-binding elements. Our data indicate that in the same species, hsp83 family genes show a higher evolution rate than the hsp70 family., (© 2013 Royal Entomological Society.)

Heat shock protein 70 (Hsp70) is a molecular chaperone providing tolerance to heat and other challenges at the cellular and organismal levels. We sequenced a genomic cluster containing three hsp70 family genes linked with major histocompatibility complex (MHC) class III region from an extremely heat tolerant animal, camel (Camelus dromedarius). Two hsp70 family genes comprising the cluster contain heat shock elements (HSEs), while the third gene lacks HSEs and should not be induced by heat shock. Comparison of the camel hsp70 cluster with the corresponding regions from several mammalian species revealed similar organization of genes forming the cluster. Specifically, the two heat inducible hsp70 genes are arranged in tandem, while the third constitutively expressed hsp70 family member is present in inverted orientation. Comparison of regulatory regions of hsp70 genes from camel and other mammals demonstrates that transcription factor matches with highest significance are located in the highly conserved 250-bp upstream region and correspond to HSEs followed by NF-Y and Sp1 binding sites. The high degree of sequence conservation leaves little room for putative camel-specific regulatory elements. Surprisingly, RT-PCR and 5'/3'-RACE analysis demonstrated that all three hsp70 genes are expressed in camel's muscle and blood cells not only after heat shock, but under normal physiological conditions as well, and may account for tolerance of camel cells to extreme environmental conditions. A high degree of evolutionary conservation observed for the hsp70 cluster always linked with MHC locus in mammals suggests an important role of such organization for coordinated functioning of these vital genes.

The accident at the Chernobyl nuclear power plant on April 26, 1986, released approximately 2 EBq of 131I and other radioiodine isotopes that heavily contaminated southern Belarus. An increase in thyroid cancer reported in 1992 and attributed to the Chernobyl accident was challenged as possibly the result of intensive screening. We began a case-control study to test the hypothesis that the Chernobyl accident caused the increase in thyroid cancer. Records of childhood thyroid cancer in the national therapy centers in Minsk in 1992 yielded 107 individuals with confirmed pathology diagnoses and available for interview. Pathways to diagnosis were (1) routine endocrinological screening in 63, (2) presentation with enlarged or nodular thyroid in 25 and (3) an incidental finding in 19. Two sets of controls were chosen, one matched on pathway to diagnosis, the other representing the area of heavy fallout, both matched on age, sex and rural/urban residence in 1986. The 131I dose to the thyroid was estimated from ground deposition of 137Cs, ground deposition of 131I, a data bank of 1986 thyroid radiation measurements, questionnaires and interviews. Highly significant differences were observed between cases and controls (both sets) with respect to dose. The differences persisted within pathway to diagnosis, gender, age and year of diagnosis, and level of iodine in the soil, and were most marked in the southern portion of the Gomel region. The case-control comparisons indicate a strong relationship between thyroid cancer and estimated radiation dose from the Chernobyl accident.

A thorough examination of 410 children with the preliminary diagnosis of neuro-arthritic diathesis revealed a family history of primary disorders of purine metabolism with hyperuricemia (HU) and hyperuricuria (HUK) in combination with borderline neuropsychic disturbances in 150 children. Most of the children (122 of the 150) presented disorders of the neurotic level of reactivity according to the type of systemic and monosystemic neuroses and neurotic reactions in the presence of moderate HU and HUK. The clinical picture in children with the signs of residual-organic cerebral insufficiency (28 of the 150) was predominantly characterized by behavioural abnormalities in conjunction with significant deviations on the part of purine metabolism parameters.