Binding of a pea nuclear protein to promoters of certain photoregulated genes is modulated by phosphorylation.
There have been numerous recent reports documenting phosphorylation of DNA-binding proteins [Montminy and Bilezikjian (1987); Sorger, Lewis, and Pelham (1987); Hoeffler, Kovelman, and Roeder (1988); Jones et al. (1988); Prywes et al. (1988); Sorger and Pelham (1988); Yamamoto et al. (1988)], and the transcriptional regulatory activity of at least one of these proteins appears to be modulated by this modification [Montminy and Bilezikjian (1987); Yamamoto et al. (1988)]. We report here on a plant nuclear protein, the DNA-binding activity of which is strongly affected by phosphorylation. This protein, AT-1, binds to specific AT-rich elements (the AT-1 box) within promoters of certain nuclear genes encoding the small subunit of ribulose-1,5-bisphosphate carboxylase and the polypeptide components of the light-harvesting chlorophyll a/b protein complex. A consensus sequence of AATATTTTTATT was derived for the AT-1 box. We demonstrate that the DNA-binding ability of AT-1, from nuclear extracts of pea, can be reversibly modulated by phosphorylation. AT-1 is active in the nonphosphorylated form and loses all DNA-binding ability as a result of phosphorylation. The kinase that phosphorylates AT-1 uses both Mg-ATP and Mg-GTP as a substrate and is inhibited by heparin and spermine, indicative of an NII-type casein kinase.
Datta
N
N
Department of Biology, University of Pennsylvania, Philadelphia 19104.
Cashmore
A R
AR
D001482:Base Composition; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA; D004268:DNA-Binding Proteins / Q000378:metabolism*; D007887:Fabaceae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D008027:Light; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics; D010940:Plant Proteins / Q000378:metabolism*; D010946:Plants, Medicinal; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics; D017385:Sequence Homology
C076980:AT-1 protein, Pisum sativum; D004268:DNA-Binding Proteins; D045342:Light-Harvesting Protein Complexes; D009687:Nuclear Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D010940:Plant Proteins; D004247:DNA; D012273:Ribulose-Bisphosphate Carboxylase