Characterization of the maize prolamin box-binding factor-1 (PBF-1) and its role in the developmental regulation of the zein multigene family.
A maize prolamin box (P-box)-binding factor (PBF-1) has been purified and characterized from immature endosperm tissue. PBF-1 has a molecular weight of 38kDa. It is detected only in endosperm, but not in root or leaf tissues, consistent with its tissue-specific function. Site-directed mutagenesis experiments reveal that both the P-box and its flanking sequences are important for PBF-1 DNA binding. Developmental studies show that PBF-1 accumulates in the endosperm from 8 to at least 30days after pollination (DAP). From 16 to 24DAP, however, multiple shifted bands of protein(s)-DNA complexes can be observed, which correlate with an increase in zein gene expression. PBF-1 can also bind to the P-box from '22-kDa' and '19-kDa' zein promoters, but at a lower affinity than to the '27-kDa' zein promoter. The effects of protein dephosphorylation and zinc ion chelators on PBF-1 DNA binding activity are also shown. A model is proposed where PBF-1 serves as a 'recruiter' of class-specific transcription factors like Opaque2 (O2).
Wang
Z
Z
Waksman Institute, Rutgers, The State University of New Jersey, Piscataway, NJ 08855-0759, USA.
Ueda
T
T
Messing
J
J
D002846:Chromatography, Affinity; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D003850:Deoxyribonuclease I; D018506:Gene Expression Regulation, Plant; D005810:Multigene Family; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development; D015028:Zein / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; C115836:PBF protein, plant; D010940:Plant Proteins; D014157:Transcription Factors; D015028:Zein; D003850:Deoxyribonuclease I