ISSN:
1573-5028
Keywords:
DNA-protein interactions
;
osmotic stress-induced promoter
;
osmotin promoter
;
pathogenesis-related protein promoter
;
promoter function
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The gene encoding osmotin, a tobacco pathogenesis-related protein, has been shown to be regulated by an array of hormonal and environmental signals. The osmotin promoter fragment −248 to −108 upstream of the transcription start site (fragment A), was sufficient to direct reporter gene expression when fused to a minimal CaMV 35S promoter in transient assays using microprojectile bombardment. This was consistent with previous 5′-deletion analyses of the osmotin promoter which showed that the promoter sequence from −248 to −108 is absolutely required for reporter gene activity. Nuclear protein factors from salt-adapted tobacco cells, ABA-treated unadapted cells, and young cultured tobacco leaves were shown to interact with fragment A by gel mobility-shift assays. DNase I footprinting revealed that three conserved promoter elements in fragment A interact specifically with nuclear factors. These elements are: (1) a cluster of G-box-like sequences (G sequence); (2) an AT-1 box-like sequence, 5′-AATTATTT-TATG-3′ (AT sequence); (3) a sequence highly conserved in ethylene-induced PR gene promoters, 5′-TAAGA/CGCCGCC-3′ (PR sequence). Transient expression assays performed with fragment A deletions fused to GUS indicated that osmotin promoter activity correlated with the presence of these elements. UV cross-linking analysis showed that the protein complex bound to fragment A consisted of at least four individual proteins with approximate molecular masses of 28, 29, 40 and 42 kDa. One component of this protein complex, which was associated with the G sequence, was a 14-3-3 like protein.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00014974
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