Characterization of the small heat shock protein Hsp27 gene in Chironomus riparius (Diptera) and its expression profile in response to temperature changes and xenobiotic exposures
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Small heat shock proteins constitute the most diverse and least conserved group within the large family of heat shock proteins, which play a crucial role in cell response to environmental insults. Chironomus riparius larvae are widely used in environmental research for testing pollutant toxicity in sediments and freshwater environments. Different genes, such as Hsp70, Hsc70, Hsp90, and Hsp40, have been identified in this species as sensitive biomarkers for xenobiotics, but small Hsps genes remain largely unknown. In this study, the Hsp27 has been characterized in C. riparius and its transcriptional response evaluated under several environmental stimuli. The Hsp27 gene was mapped by FISH on polytene chromosomes at region I-C4 and was found to encode a 195 aa protein, which contains an α-crystallin domain bounded by three conserved regions. This protein shows homology with Drosophila melanogaster HSP27, Ceratitis capitata HSP27, and Sarcophaga crassipalpis HSP25. Real-time reverse transcriptase–polymerase chain reaction analysis showed that heat shock (35 °C) and cadmium dramatically upregulate this gene. Moreover, exposures to triclosan and bisphenol A were able to significantly increase mRNA levels. However, neither nonylphenol nor tributyltin altered Hsp27 gene expression. The transcriptional activity of Hsp27 gene was modulated during cold stress. Interestingly, cold shock (4 °C) significantly reduced Hsp27 transcripts, but this gene was significantly overexpressed during the recovery time at the normal growing temperature. These results show that the Hsp27 gene is sensitive to different environmental stimuli, including endocrine-disrupting pollutants, suggesting its potential as a suitable biomarker for ecotoxicological studies in aquatic systems.
KeywordsCold heat shock Cadmium Bisphenol A (BPA) 4-Nonylphenol (NP) Tributyltin (TBT) Triclosan (TCS)
The authors wish to thank Dr T. Carretero (University of Zaragoza) and Ted Cater for critical reading of the manuscript. This work was supported by the Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica (Spain), grant CTM2012-37547 from the Ciencias y Tecnologías Medioambientales program. The authors declare that there are no conflicts of interest.
- Chen CP, Denlinger DL, Lee RE (1987) Cold-shock injury and rapid cold hardening in the flesh fly Sarcophaga crassipalpis. Physiol Zool 60:297–304Google Scholar
- EPA (US) (1996) Chironomid sediment toxicity test, ecological effects test guidelines. EPA 712-C-96-313; 2nd ed. EPA 600/R-99/064, Washington DC, USAGoogle Scholar
- Gopalakrishnan Nair PM, Park SY, Lee SW, Choi J (2011) Differential expression of ribosomal protein gene, gonadotrophin relasing hormone gene and Balbiani ring protein gene in silver nanoparticles exposed Chironomus riparius. Aquat Toxicol 101:31–37Google Scholar
- Hoffmann AA, Parsons PA (1991) Evolutionary genetics and environmental stress. Oxford University Press, New YorkGoogle Scholar
- Martínez-Paz P, Morales M, Martínez-Guitarte JL, Morcillo G (2012) Characterization of a cytochrome P450 gene (CYP4G) and modulation under different exposures to xenobiotics (tributyltin, nonylphenol, bisphenol A) in Chironomus riparius aquatic larvae. Comp Biochem Physiol C-Toxicol Pharmacol 155:333–343PubMedCrossRefGoogle Scholar
- Morales M, Planelló R, Martínez-Paz P, Herrero O, Cortés E, Martínez-Guitarte JL, Morcillo G (2011) Characterization of Hsp70 gene in Chironomus riparius: expression in response to endocrine disrupting pollutants as a marker of ecotoxicological stress. Comp Biochem Physiol C-Toxicol Pharmacol 153:150–158PubMedCrossRefGoogle Scholar
- Nolen EAA, Morimoto RI (2002) Chaperoning signaling pathways: molecular chaperones as stress-sensing heat shock proteins. J Cell Sci 115:2809–2816Google Scholar
- OECD. Organisation for Economic Co-operation and Development (2001) Guideline for testing of chemicals, sediment-water chironomid toxicity test using spiked sediment. 218 ppGoogle Scholar
- Park K, Kwak IS (2009) Alcohol dehydrogenase gene expression in Chironomus riparius exposed to di(2-ethylhexyl) phthalate. Comp Biochem Comp Biochem Physiol C-Toxicol Pharmaco 150361–367Google Scholar
- Planelló R, Herrrero O, Martínez-Guitarte JL, Morcillo G (2011) Comparative effects of butyl benzyl phthalate (BBP) and di-2-ethylhexyl phthalate (DEHP) on the aquatic larvae of Chironomus riparius based on gene expression assays related to the endocrine system, the stress response and ribosomes. Aquat Toxicol 105:62–70PubMedCrossRefGoogle Scholar
- Sonoda S, Ashfaq M, Tsumuki H (2006) Cloning and nucleotide sequencing of three heat shock protein genes (hsp90, hsc70 and hsp19.5) from the Diamondback moth, Plutella xylostella (L.) and their expression in relation to developmental stage and temperature. Arch Insect Biochem Physiol 62:80–90PubMedCrossRefGoogle Scholar