title: The HSP70 chaperone machines of Chlamydomonas are induced by cold stress.
abstract: The responses of Chlamydomonas reinhardtii cells to low temperatures have not been extensively studied compared with other stresses. Like other organisms, this green alga has heat shock protein 70s (HSP70s) that are located in chloroplast, mitochondrion and cytosol. To test whether temperature downshifts affected HSP70s synthesis, we used real-time PCR and protein gel blot analysis. C. reinhardtii cells exposed to cold stress show increased HSP70s mRNA levels. Genes encoding other components of HSP70 chaperone machines (e.g. CGE1, CDJ1, HSP90C and HSP90A) are also up-regulated in response to decreased temperature. We demonstrated that the accumulation of all analyzed mRNA occur more slowly and with reduced amplitude in cells exposed to cold than in cells treated with heat. Furthermore, C. reinhardtii cells display the splicing of the CGE1 transcript that was dependent on low temperature. Finally, the transcription regulator of C. reinhardtii HSF1 is also cold-responsive, suggesting its role in the transcriptional regulation of HSP genes at low temperature.
authors.affiliation: Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia.
authors.forename: Anna
authors.initials: A
authors.lastname: Maikova
authors.affiliation: Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia.
authors.forename: Zhanneta
authors.initials: Z
authors.lastname: Zalutskaya
authors.affiliation: Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Lapina
authors.affiliation: Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia. Electronic address: e.ermilova@spbu.ru.
authors.forename: Elena
authors.initials: E
authors.lastname: Ermilova
mesh_terms: D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003080:Cold Temperature; D018506:Gene Expression Regulation, Plant; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological
chemical_list: D018840:HSP70 Heat-Shock Proteins; D010940:Plant Proteins; D012333:RNA, Messenger
keywords: Chlamydomonas reinhardtii; Cold stress; Gene expression; Heat shock proteins; Quantitative real-time RT-PCR