caa a22 4500 606230459 CHVBK 20210128101214.0 cr unu---uuuuu 210128e20151001xx s 000 0 eng 10.1007/s10695-015-0077-2 doi (NATIONALLICENCE)springer-10.1007/s10695-015-0077-2 c-myc in whitefish ( Coregonus lavaretus ): structure, expression, and insights into possible posttranscriptional regulatory mechanism [Elektronische Daten] [P. Brzuzan, C. Kramer, A. Łakomiak, E. Jakimiuk, M. Florczyk, M. Woźny] c-myc has a crucial function in growth control, differentiation, and apoptosis of vertebrate cells. Despite the important role of c-myc in mediating the biological effects, studies of c-myc gene expression and factors that control it in organisms other than mammals, such as fish, have been rare. In the current study, we asked whether c-myc mRNA of whitefish, a feasible organism for pollution monitoring in aquatic systems and a model in toxicological research, contains activity sites for regulatory motifs in its 5′- and 3′-UTRs, similar to those found in mammals. We were particularly interested in whether miRNA-34, a known negative regulator of c-myc's in mammals, is able to regulate c-myc in fish. To answer these questions, we determined the mRNA sequence of whitefish c-myc and inferred the structure of the protein that it codes for. We found that the active sites of mRNA and structures of the inferred c-myc protein are similar to those found in mammals and other fish. Remarkably, levels of c-myc mRNA expression were very high in ovaries compared to other tissues of whitefish, thus corroborating previous data in fish. Using bioinformatic searches on c-myc 3′-UTR, we confirmed the presence of two miRNA-34a(miR-34a)response elements. Luciferase reporter assay showed that activity of reporters containing either the miR response elements or entire c-myc 3′-UTR was significantly reduced (p<0.001) by ectopic expression of miR-34a. Therefore, we further investigated possible involvement of miR-34a in c-myc gene silencing by profiling the expression of both genes in livers of whitefish treated for 8, 24, 48h with MC-LR, a potent c-myc inducer in mammals. Although the difference was only significant at p=0.08, the expression of c-myc mRNA in challenged whitefish after 24h of the treatment was notably higher than that in livers of control fish. Concurrently, we noticed slight but significant up-regulation of miR-34a after 24 and 48h of the challenge (p<0.05); however, we found no significant correlation of the c-myc mRNA levels and miR-34a expression. Together, these results suggest that miR-34a might regulate c-myc gene expression in whitefish liver; however, their involvement in MC-LR hepatotoxicity should be clarified in future studies. Springer Science+Business Media Dordrecht, 2015 c-myc nationallicence Microcystin-LR nationallicence MicroRNA nationallicence miR-34a nationallicence Reporter analysis nationallicence Brzuzan P. Department of Environmental Biotechnology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, ul. Słoneczna 45G, 10-709, Olsztyn, Poland aut Kramer C. Department of Environmental Biotechnology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, ul. Słoneczna 45G, 10-709, Olsztyn, Poland aut Łakomiak A. Department of Environmental Biotechnology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, ul. Słoneczna 45G, 10-709, Olsztyn, Poland aut Jakimiuk E. Department of Veterinary Prevention and Feed Hygiene, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 13, 10-950, Olsztyn, Poland aut Florczyk M. Department of Environmental Biotechnology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, ul. Słoneczna 45G, 10-709, Olsztyn, Poland aut Woźny M. Department of Environmental Biotechnology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, ul. Słoneczna 45G, 10-709, Olsztyn, Poland aut Fish Physiology and Biochemistry Springer Netherlands 41/5(2015-10-01), 1155-1171 0920-1742 41:5<1155 2015 41 10695 https://doi.org/10.1007/s10695-015-0077-2 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10695-015-0077-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Brzuzan P. Department of Environmental Biotechnology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, ul. Słoneczna 45G, 10-709, Olsztyn, Poland aut NATIONALLICENCE 700 1- Kramer C. Department of Environmental Biotechnology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, ul. Słoneczna 45G, 10-709, Olsztyn, Poland aut NATIONALLICENCE 700 1- Łakomiak A. Department of Environmental Biotechnology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, ul. Słoneczna 45G, 10-709, Olsztyn, Poland aut NATIONALLICENCE 700 1- Jakimiuk E. Department of Veterinary Prevention and Feed Hygiene, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 13, 10-950, Olsztyn, Poland aut NATIONALLICENCE 700 1- Florczyk M. Department of Environmental Biotechnology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, ul. Słoneczna 45G, 10-709, Olsztyn, Poland aut NATIONALLICENCE 700 1- Woźny M. Department of Environmental Biotechnology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, ul. Słoneczna 45G, 10-709, Olsztyn, Poland aut NATIONALLICENCE 773 0- Fish Physiology and Biochemistry Springer Netherlands 41/5(2015-10-01), 1155-1171 0920-1742 41:5<1155 2015 41 10695