title: Gene expression profiles of cytosolic heat shock proteins Hsp70 and Hsp90 from symbiotic dinoflagellates in response to thermal stress: possible implications for coral bleaching.
abstract: Unicellular photosynthetic dinoflagellates of the genus Symbiodinium are the most common endosymbionts of reef-building scleractinian corals, living in a symbiotic partnership known to be highly susceptible to environmental changes such as hyperthermic stress. In this study, we identified members of two major heat shock proteins (HSPs) families, Hsp70 and Hsp90, in Symbiodinium sp. (clade C) with full-length sequences that showed the highest similarity and evolutionary relationship with other known HSPs from dinoflagellate protists. Regulation of HSPs gene expression was examined in samples of the scleractinian coral Acropora millepora subjected to elevated temperatures progressively over 18 h (fast) and 120 h (gradual thermal stress). Moderate to severe heat stress at 26°C and 29°C (+3°C and +6°C above average sea temperature) resulted in an increase in algal Hsp70 gene expression from 39% to 57%, while extreme heat stress (+9°C) reduced Hsp70 transcript abundance by 60% (after 18 h) and 70% (after 120 h). Elevated temperatures decreased an Hsp90 expression under both rapid and gradual heat stress scenarios. Comparable Hsp70 and Hsp90 gene expression patterns were observed in Symbiodinium cultures and in hospite, indicating their independent regulation from the host. Differential gene expression profiles observed for Hsp70 and Hsp90 suggests diverse roles of these molecular chaperones during heat stress response. Reduced expression of the Hsp90 gene under heat stress can indicate a reduced role in inhibiting the heat shock transcription factor which may lead to activation of heat-inducible genes and heat acclimation.
authors.affiliation: Global Change Institute, The University of Queensland, St. Lucia, 4072, Queensland, Australia. n.rosic@uq.edu.au
authors.forename: Nedeljka N
authors.initials: NN
authors.lastname: Rosic
authors.forename: Mathieu
authors.initials: M
authors.lastname: Pernice
authors.forename: Sophie
authors.initials: S
authors.lastname: Dove
authors.forename: Simon
authors.initials: S
authors.lastname: Dunn
authors.forename: Ove
authors.initials: O
authors.lastname: Hoegh-Guldberg
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004141:Dinoflagellida / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D018840:HSP70 Heat-Shock Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D018841:HSP90 Heat-Shock Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D013559:Symbiosis; D013696:Temperature; D013997:Time Factors
chemical_list: D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins
references.citation: Mar Biotechnol (NY). 2000 Nov;2(6):533-44
references.pmid: 14961177
references.citation: Mol Phylogenet Evol. 2006 Jan;38(1):20-30
references.pmid: 15978847
references.citation: J Evol Biol. 2005 Jul;18(4):744-9
references.pmid: 16033544
references.citation: Biol Chem. 1998 Mar;379(3):245-59
references.pmid: 9563819
references.citation: BMC Genomics. 2006 Jun 17;7:156
references.pmid: 16780600
references.citation: Nat Rev Mol Cell Biol. 2004 Oct;5(10):781-91
references.pmid: 15459659
references.citation: Biochem Biophys Res Commun. 2006 Sep 22;348(2):585-92
references.pmid: 16884692
references.citation: Prikl Biokhim Mikrobiol. 2008 May-Jun;44(3):343-6
references.pmid: 18663961
references.citation: Mol Ecol. 2009 Dec;18(24):5101-14
references.pmid: 19900172
references.citation: J Biosci. 2007 Apr;32(3):595-610
references.pmid: 17536179
references.citation: Mar Biotechnol (NY). 2011 Jun;13(3):355-65
references.pmid: 20668900
references.citation: J Exp Biol. 2010 Apr;213(Pt 7):1026-34
references.pmid: 20228338
references.citation: BMC Genomics. 2009 Dec 23;10:627
references.pmid: 20030803
references.citation: Genome Biol. 2002 Jun 18;3(7):RESEARCH0034
references.pmid: 12184808
references.citation: Mol Biol Evol. 1995 Nov;12(6):1063-73
references.pmid: 8524040
references.citation: J Exp Biol. 2008 Oct;211(Pt 19):3059-66
references.pmid: 18805804
references.citation: Gene. 2007 Jul 1;396(1):84-92
references.pmid: 17433575
references.citation: Curr Genomics. 2008;9(5):338-248
references.pmid: 19471609
references.citation: Proc Natl Acad Sci U S A. 2008 Feb 26;105(8):2969-74
references.pmid: 18287064
references.citation: Proc Natl Acad Sci U S A. 2009 Mar 3;106(9):3237-42
references.pmid: 19202067
references.citation: Can J Microbiol. 1962 Apr;8:229-39
references.pmid: 13902807
references.citation: J Eukaryot Microbiol. 2002 Jan-Feb;49(1):30-7
references.pmid: 11908896
references.citation: Cell Stress Chaperones. 2001 Jul;6(3):201-8
references.pmid: 11599561
references.citation: Cell Stress Chaperones. 2009 Nov;14(6):649-60
references.pmid: 19404777
references.citation: PLoS One. 2009 Jul 24;4(7):e6364
references.pmid: 19629182
references.citation: Proc Natl Acad Sci U S A. 1992 Nov 1;89(21):10302-5
references.pmid: 11607337
references.citation: Curr Protoc Immunol. 2004 Feb;Appendix 1:Appendix 1T
references.pmid: 18432918
references.citation: Biochem J. 2008 Mar 15;410(3):439-53
references.pmid: 18290764
references.citation: Mar Genomics. 2009 Mar;2(1):11-8
references.pmid: 21798167
references.citation: Nature. 1998 Nov 26;396(6709):336-42
references.pmid: 9845070
references.citation: Science. 2010 Jul 16;329(5989):322-5
references.pmid: 20647466
references.citation: Dev Genes Evol. 2007 Aug;217(8):603-12
references.pmid: 17647016
references.citation: Plant Signal Behav. 2008 Sep;3(9):660-2
references.pmid: 19704818
references.citation: Cell Stress Chaperones. 2010 Jan;15(1):83-93
references.pmid: 19496024
references.citation: Science. 2007 Dec 14;318(5857):1737-42
references.pmid: 18079392
references.citation: PLoS One. 2010 Mar 18;5(3):e9751
references.pmid: 20305781
references.citation: Mol Ecol. 2006 Nov;15(13):3863-83
references.pmid: 17054489
references.citation: Proc Natl Acad Sci U S A. 2000 Apr 11;97(8):4392-7
references.pmid: 10760305
references.citation: Crit Rev Biochem Mol Biol. 2007 Sep-Oct;42(5):355-72
references.pmid: 17917872
references.citation: Proc Natl Acad Sci U S A. 2008 Mar 18;105(11):4203-8
references.pmid: 18322010
references.citation: Pharmacol Ther. 1998 Aug;79(2):129-68
references.pmid: 9749880
references.citation: J Cell Biol. 2001 Jul 23;154(2):267-73
references.pmid: 11470816
references.citation: Mol Ecol. 2010 Mar;19(6):1174-86
references.pmid: 20149089
references.citation: Appl Environ Microbiol. 2010 May;76(9):2823-9
references.pmid: 20228102
references.citation: Semin Cell Dev Biol. 2003 Oct;14(5):267-74
references.pmid: 14986856
references.citation: J Biol Chem. 1989 Oct 15;264(29):17275-80
references.pmid: 2507541
references.citation: Cell. 1998 Aug 21;94(4):471-80
references.pmid: 9727490
references.citation: Protist. 2005 Jun;156(1):19-34
references.pmid: 16048130
references.citation: Fish Shellfish Immunol. 2008 Apr;24(4):379-85
references.pmid: 18282767
references.citation: J Exp Bot. 2008;59(5):1069-80
references.pmid: 18267943
references.citation: Mol Biol Evol. 2001 Jul;18(7):1272-82
references.pmid: 11420366
references.citation: Science. 2002 Apr 19;296(5567):557-9
references.pmid: 11964485
references.citation: J Exp Biol. 2004 Jan;207(Pt 1):15-9
references.pmid: 14638828
references.citation: J Exp Biol. 2005 Jan;208(Pt 2):277-85
references.pmid: 15634847
references.citation: Proc Natl Acad Sci U S A. 2007 Mar 27;104(13):5259-60
references.pmid: 17374718
references.citation: J Exp Biol. 2008 Apr;211(Pt 7):1050-6
references.pmid: 18344478
references.citation: Nucleic Acids Res. 1994 Nov 11;22(22):4673-80
references.pmid: 7984417
references.citation: Insect Mol Biol. 2006 Dec;15(6):839-52
references.pmid: 17201776
references.citation: Annu Rev Physiol. 1999;61:243-82
references.pmid: 10099689
references.citation: Biochim Biophys Acta. 1992 Aug 17;1132(1):26-34
references.pmid: 1511010