The pollen-specific DEFH125 promoter from Antirrhinum is bound in vivo by the MADS-box proteins DEFICIENS and GLOBOSA.
The Antirrhinum DEFH125 MADS-box protein is expressed in maturing pollen and thus likely participates in the regulation of pollen development. Here, we describe the characterization of a 2.5 kbp promoter fragment conferring pollen-specific GUS expression in Antirrhinum, as well as in the distantly related species Arabidopsis. Taking advantage of the higher sensitivity of the diphtheria toxin A-chain (DTA) reporter gene assay, onset of DEFH125 promoter activity could be defined to start at the late unicellular microspore stage. Stamen development in Antirrhinum is governed by the class B MADS-box genes DEFICIENS (DEF) and GLOBOSA (GLO). The respective proteins form a heterodimer and are expressed throughout stamens, except for microspores. Complementary expression patterns of DEFH125 and DEF/GLO during later stamen development tempted us to investigate whether the DEF/GLO heterodimer might bind the DEFH125 promoter and could thus be involved in repressing the DEFH125 expression. The ChIP technique was applied to investigate protein/DNA interactions occurring in vivo. We report the identification of a 200 bp DEFH125 promoter fragment that is in vivo bound by DEF and GLO proteins. This fragment contains a CArG-box motif, known to mediate DNA binding of MADS-box proteins. Implications for a likely function of DEF and GLO in the transcriptional control of DEFH125 are discussed.
Lauri
Andrea
A
Max Planck Institute for Plant Breeding Research, 50829 Köln, Germany.
Xing
Shuping
S
Heidmann
Iris
I
Saedler
Heinz
H
Zachgo
Sabine
S
D032161:Antirrhinum / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics; D001483:Base Sequence; D047369:Chromatin Immunoprecipitation / Q000379:methods; D026281:DEFICIENS Protein / Q000378:metabolism*; D004167:Diphtheria Toxin / Q000235:genetics; D035264:Flowers / Q000378:metabolism; D005966:Glucuronidase / Q000032:analysis; D018398:Homeodomain Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000166:cytology / Q000378:metabolism; D011058:Pollen / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D025941:Protein Interaction Mapping; D011993:Recombinant Fusion Proteins / Q000032:analysis
D026281:DEFICIENS Protein; D004167:Diphtheria Toxin; C102172:GLOBOSA protein, plant; D018398:Homeodomain Proteins; D010446:Peptide Fragments; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C029795:diphtheria toxin fragment A; D005966:Glucuronidase