Nuclear factors interact with conserved A/T-rich elements upstream of a nodule-enhanced glutamine synthetase gene from French bean.
The gln-gamma gene, encoding the gamma subunit of glutamine synthetase in French bean (Phaseolus vulgaris), is strongly induced during nodule development. We have determined the nucleotide sequence of a 1.3-kilobase region at its 5' end and have identified several sequences common to the promoter regions of late nodulin genes from other legume species. The 5'-flanking region was analyzed for sequence-specific interactions with nuclear factors from French bean. A factor from nodules (PNF-1) was identified that binds to multiple sites between -860 and -154, and a related but distinct factor (PRF-1) was detected in extracts from uninfected roots. PNF-1 and PRF-1 bound strongly to a synthetic oligonucleotide containing the sequence of an A/T-rich 21-base pair imperfect repeat found at positions -516 and -466. The same factors also had a high affinity for a protein binding site from a soybean leghemoglobin gene and appeared to be closely related to the soybean nodule factor NAT2, which binds to A/T-rich sequences in the lbc3 and nodulin 23 genes [Jacobsen et al. (1990). Plant Cell 2, 85-94]. Comparison of NAT2/PNF-1 binding sites from a variety of nodulin genes revealed the conservation of the short consensus core motif TATTTWAT, and evidence was obtained that this sequence is important for protein recognition. Cross-recognition by PNF-1 of a protein binding site in a soybean seed protein gene points to the existence of a ubiquitous family of factors with related binding affinities. Our data suggest that PNF-1 and PRF-1 belong to an evolutionarily conserved group of nuclear factors that interact with specific A/T-rich sequences in a diverse set of plant genes. We consider the possible role of these factors in coregulating the expression of gln-gamma and other late nodulin genes.
Forde
B G
BG
Biochemistry and Physiology Department, AFRC Institute of Arable Crops Research, Harpenden, United Kingdom.
Freeman
J
J
Oliver
J E
JE
Pineda
M
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000378:metabolism*; D007887:Fabaceae / Q000201:enzymology* / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D005974:Glutamate-Ammonia Ligase / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D010946:Plants, Medicinal; D011401:Promoter Regions, Genetic / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D010940:Plant Proteins; D005974:Glutamate-Ammonia Ligase