Hypoxia responsive gene expression is mediated by various subsets of transcription factors and miRNAs that are determined by the actual oxygen availability.
• Reduced oxygen availability is not only associated with flooding, but occurs also during growth and development. It is largely unknown how hypoxia is perceived and what signaling cascade is involved in activating adaptive responses. • We analysed the expression of over 1900 transcription factors (TFs) and 180 microRNA primary transcripts (pri-miRNAs) in Arabidopsis roots exposed to different hypoxic conditions by means of quantitative PCR. We also analysed the promoters of genes induced by hypoxia with respect to over-represented DNA elements that can act as potential TF binding sites and their in vivo interaction was verified. • We identified various subsets of TFs that responded differentially through time and in an oxygen concentration-dependent manner. The regulatory potential of selected TFs and their predicted DNA binding elements was validated. Although the expression of pri-miRNAs was differentially regulated under hypoxia, only one corresponding mature miRNA changed accordingly. Putative target transcripts of the miRNAs were not significantly affected. • Our results show that the regulation of hypoxia-induced genes is controlled via simultaneous interaction of various combinations of TFs. Under anoxic conditions, an additional set of TFs is induced. Regulation of gene expression via miRNAs appears to play a minor role during hypoxia.
Licausi
Francesco
F
Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany. licausi@mpimp-golm.mpg.de
Weits
Daan A
DA
Pant
Bikram Datt
BD
Scheible
Wolf-Rüdiger
WR
Geigenberger
Peter
P
van Dongen
Joost T
JT
D017360:Arabidopsis / Q000166:cytology* / Q000187:drug effects / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D015687:Cell Hypoxia / Q000187:drug effects / Q000235:genetics; D018744:DNA, Plant / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017343:Genes, Plant / Q000235:genetics; D007210:Indoleacetic Acids / Q000378:metabolism; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010100:Oxygen / Q000494:pharmacology*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects
D029681:Arabidopsis Proteins; D018744:DNA, Plant; D007210:Indoleacetic Acids; D035683:MicroRNAs; D012333:RNA, Messenger; D014157:Transcription Factors; D010100:Oxygen