title: Heme oxygenase up-regulation under ultraviolet-B radiation is not epigenetically restricted and involves specific stress-related transcriptions factors.
abstract: Heme oxygenase-1 (HO-1) plays a protective role against oxidative stress in plants. The mechanisms regulating its expression, however, remain unclear. Here we studied the methylation state of a GC rich HO-1 promoter region and the expression of several stress-related transcription factors (TFs) in soybean plants subjected to ultraviolet-B (UV-B) radiation. Genomic DNA and total RNA were isolated from leaves of plants irradiated with 7.5 and 15kJm-2 UV-B. A 304bp HO-1 promoter region was amplified by PCR from sodium bisulfite-treated DNA, cloned into pGEMT plasmid vector and evaluated by DNA sequencing. Bisulfite sequencing analysis showed similar HO-1 promoter methylation levels in control and UV-B-treated plants (C: 3.4±1.3%; 7.5: 2.6±0.5%; 15: 3.1±1.1%). Interestingly, HO-1 promoter was strongly unmethylated in control plants. Quantitative RT-PCR analysis of TFs showed that GmMYB177, GmMYBJ6, GmWRKY21, GmNAC11, GmNAC20 and GmGT2A but not GmWRK13 and GmDREB were induced by UV-B radiation. The expression of several TFs was also enhanced by hemin, a potent and specific HO inducer, inferring that they may mediate HO-1 up-regulation. These results suggest that soybean HO-1 gene expression is not epigenetically regulated. Moreover, the low level of HO-1 promoter methylation suggests that this antioxidant enzyme can rapidly respond to environmental stress. Finally, this study has identified some stress-related TFs involved in HO-1 up-regulation under UV-B radiation.
authors.affiliation: Laboratorio de Regulación Génica y Células Madre, Instituto de Medicina Traslacional, Trasplante y Bioingeniería (IMeTTyB), Universidad Favaloro-CONICET, Buenos Aires, Argentina; Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA), Facultad de Agronomía, Buenos Aires, Argentina.
authors.forename: Diego
authors.initials: D
authors.lastname: Santa-Cruz
authors.affiliation: Laboratorio de Regulación Génica y Células Madre, Instituto de Medicina Traslacional, Trasplante y Bioingeniería (IMeTTyB), Universidad Favaloro-CONICET, Buenos Aires, Argentina.
authors.forename: Natalia
authors.initials: N
authors.lastname: Pacienza
authors.affiliation: Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA), Facultad de Agronomía, Buenos Aires, Argentina.
authors.forename: Carla
authors.initials: C
authors.lastname: Zilli
authors.affiliation: Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA), Facultad de Agronomía, Buenos Aires, Argentina.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Pagano
authors.affiliation: Universidad de Buenos Aires (UBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA), Facultad de Agronomía, Buenos Aires, Argentina. Electronic address: kbale@agro.uba.ar.
authors.forename: Karina
authors.initials: K
authors.lastname: Balestrasse
authors.affiliation: Laboratorio de Regulación Génica y Células Madre, Instituto de Medicina Traslacional, Trasplante y Bioingeniería (IMeTTyB), Universidad Favaloro-CONICET, Buenos Aires, Argentina. Electronic address: gyannarelli@favaloro.edu.ar.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Yannarelli
mesh_terms: D019175:DNA Methylation; D044127:Epigenesis, Genetic / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics*; D018384:Oxidative Stress; D018515:Plant Leaves / Q000235:genetics / Q000528:radiation effects; D010940:Plant Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000528:radiation effects; D017422:Sequence Analysis, DNA; D013025:Glycine max / Q000235:genetics / Q000528:radiation effects*; D014157:Transcription Factors / Q000235:genetics*; D015854:Up-Regulation
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors; D006419:Heme Oxygenase (Decyclizing)
keywords: DNA methylation; Glycine max; Heme oxygenase; Transcription factors; Ultraviolet-B radiation