Tissue-specific regulation of BiP genes: a cis-acting regulatory domain is required for BiP promoter activity in plant meristems.
The binding protein BiP is an endoplasmic reticulum (ER)-resident member of the HSP70 stress-related protein family, which is essential for the constitutive function of the ER. In addition to responding to a variety of environmental stimuli, plant BiP exhibits a tissue-specific regulation. We have isolated two soybean BiP genomic clones, designated gsBiP6 and gsBiP9, and different extensions of their 5' flanking sequences were fused to beta-glucuronidase (GUS) reporter gene and introduced into Nicotiana tabacum by Agrobacterium tumefaciens-mediated transformation. Transgenic plants displayed prominent GUS activity in the vascular bundles of roots and shoots as well as in regions of intense cell division, such as procambial region and apical meristems. Promoter deletion analyses identified two cis-regulatory functional domains that are important for the spatially-regulated activation of BiP expression under normal plant development. While an AT-rich enhancer-like sequence, designated cis-acting regulatory domain 1, CRD1 (-358 to -211, on gsBiP6), activated expression of the BiP minimal promoter in all organs analyzed, BiP promoter activity in meristematic tissues and phloem cells required the presence of a second activating domain, CRD2 (-211 to -80). Apparently, the CRD2 sequence also harbors negative cis-acting elements, because removal of this region caused activation of gsBiP6 promoter in parenchymatic xylem rays. These results suggest that the tissue-specific control of BiP gene expression requires a complex integration of multiple cis-acting regulatory elements on the promoter.
Buzeli
Reginaldo A A
RA
Departamento de Biologia Vegetal, BIOAGRO, UFV, Viçosa, MG, Brazil.
Cascardo
Júlio C M
JC
Rodrigues
Leonardo A Z
LA
Andrade
Maxuel O
MO
Almeida
Raul S
RS
Loureiro
Marcelo E
ME
Otoni
Wagner C
WC
Fontes
Elizabeth P B
EP
D029681:Arabidopsis Proteins; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D017124:Conserved Sequence / Q000235:genetics; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005057:Eukaryotic Cells / Q000166:cytology / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D018519:Meristem / Q000235:genetics*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics*; D018520:Plant Shoots / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013025:Glycine max / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics; D024363:Transcription Initiation Site
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D018744:DNA, Plant; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C077221:BIP protein, Arabidopsis; D005966:Glucuronidase