The virB operon of Agrobacterium tumefaciens pTiC58 encodes 11 open reading frames

Gretchen Anna Kuldau, Guido De Vos, John Owen, Gretchen McCaffrey, Patricia Zambryski

Research output: Contribution to journalArticle

86 Citations (Scopus)

Abstract

Agrobacterium tumefaciens genetically transforms plant cells by transferring a copy of its T-DNA to the plant where it is integrated and stably maintained. In the presence of wounded plant cells this process is activated and mediated by the products of the vir genes which are grouped into six distinct loci. The largest is the virB locus spanning 9.5 kb. Transposon mutagenesis studies have shown that virB gene products are required for virulence but their functions remain largely unknown. To provide information relevant to understanding the function of VirB polypeptides, the nucleotide sequence of the virB operon from a nopaline plasmid, pTiC58, is presented here. Eleven open reading frames (ORFs) are predicted from this sequence. The predicted sizes of 10 of the 11 VirB polypeptides are verified by specific expression in Escherichia coli. Only the product of the smallest ORF potentially encoding a 5.8 kDa polypeptide has not been detected. The initiation of translation of five virB ORFs occurs at codons that overlap the termination codons of the ORF immediately upstream; thus, translational coupling may be an important mechanism for efficient translation of the large virB polycistronic mRNA. Based on hydropathy plot analysis nine of the virB ORFs encode proteins that may interact with membranes; these data support the earlier hypothesis (Engstromm et al. 1987) that virB gene products may form a membrane pore or channel to mediate exit of the T-DNA copy (T-strands) from Agrobacterium into the plant cell. A comparison of the two published octopine virB sequences with the nopaline sequence presented here is made.

Original languageEnglish (US)
Pages (from-to)256-266
Number of pages11
JournalMGG Molecular & General Genetics
Volume221
Issue number2
DOIs
StatePublished - Apr 1 1990

Fingerprint

Agrobacterium tumefaciens
Operon
Open Reading Frames
Plant Cells
Peptides
Genes
Agrobacterium
Membranes
Terminator Codon
Codon
Mutagenesis
Virulence
Plasmids
Escherichia coli
Messenger RNA
Proteins

All Science Journal Classification (ASJC) codes

  • Genetics

Cite this

Kuldau, Gretchen Anna ; De Vos, Guido ; Owen, John ; McCaffrey, Gretchen ; Zambryski, Patricia. / The virB operon of Agrobacterium tumefaciens pTiC58 encodes 11 open reading frames. In: MGG Molecular & General Genetics. 1990 ; Vol. 221, No. 2. pp. 256-266.
@article{4218381977914a278c5d88758ee1e88c,
title = "The virB operon of Agrobacterium tumefaciens pTiC58 encodes 11 open reading frames",
abstract = "Agrobacterium tumefaciens genetically transforms plant cells by transferring a copy of its T-DNA to the plant where it is integrated and stably maintained. In the presence of wounded plant cells this process is activated and mediated by the products of the vir genes which are grouped into six distinct loci. The largest is the virB locus spanning 9.5 kb. Transposon mutagenesis studies have shown that virB gene products are required for virulence but their functions remain largely unknown. To provide information relevant to understanding the function of VirB polypeptides, the nucleotide sequence of the virB operon from a nopaline plasmid, pTiC58, is presented here. Eleven open reading frames (ORFs) are predicted from this sequence. The predicted sizes of 10 of the 11 VirB polypeptides are verified by specific expression in Escherichia coli. Only the product of the smallest ORF potentially encoding a 5.8 kDa polypeptide has not been detected. The initiation of translation of five virB ORFs occurs at codons that overlap the termination codons of the ORF immediately upstream; thus, translational coupling may be an important mechanism for efficient translation of the large virB polycistronic mRNA. Based on hydropathy plot analysis nine of the virB ORFs encode proteins that may interact with membranes; these data support the earlier hypothesis (Engstromm et al. 1987) that virB gene products may form a membrane pore or channel to mediate exit of the T-DNA copy (T-strands) from Agrobacterium into the plant cell. A comparison of the two published octopine virB sequences with the nopaline sequence presented here is made.",
author = "Kuldau, {Gretchen Anna} and {De Vos}, Guido and John Owen and Gretchen McCaffrey and Patricia Zambryski",
year = "1990",
month = "4",
day = "1",
doi = "10.1007/BF00261729",
language = "English (US)",
volume = "221",
pages = "256--266",
journal = "Molecular Genetics and Genomics",
issn = "1617-4615",
publisher = "Springer Verlag",
number = "2",

}

The virB operon of Agrobacterium tumefaciens pTiC58 encodes 11 open reading frames. / Kuldau, Gretchen Anna; De Vos, Guido; Owen, John; McCaffrey, Gretchen; Zambryski, Patricia.

In: MGG Molecular & General Genetics, Vol. 221, No. 2, 01.04.1990, p. 256-266.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The virB operon of Agrobacterium tumefaciens pTiC58 encodes 11 open reading frames

AU - Kuldau, Gretchen Anna

AU - De Vos, Guido

AU - Owen, John

AU - McCaffrey, Gretchen

AU - Zambryski, Patricia

PY - 1990/4/1

Y1 - 1990/4/1

N2 - Agrobacterium tumefaciens genetically transforms plant cells by transferring a copy of its T-DNA to the plant where it is integrated and stably maintained. In the presence of wounded plant cells this process is activated and mediated by the products of the vir genes which are grouped into six distinct loci. The largest is the virB locus spanning 9.5 kb. Transposon mutagenesis studies have shown that virB gene products are required for virulence but their functions remain largely unknown. To provide information relevant to understanding the function of VirB polypeptides, the nucleotide sequence of the virB operon from a nopaline plasmid, pTiC58, is presented here. Eleven open reading frames (ORFs) are predicted from this sequence. The predicted sizes of 10 of the 11 VirB polypeptides are verified by specific expression in Escherichia coli. Only the product of the smallest ORF potentially encoding a 5.8 kDa polypeptide has not been detected. The initiation of translation of five virB ORFs occurs at codons that overlap the termination codons of the ORF immediately upstream; thus, translational coupling may be an important mechanism for efficient translation of the large virB polycistronic mRNA. Based on hydropathy plot analysis nine of the virB ORFs encode proteins that may interact with membranes; these data support the earlier hypothesis (Engstromm et al. 1987) that virB gene products may form a membrane pore or channel to mediate exit of the T-DNA copy (T-strands) from Agrobacterium into the plant cell. A comparison of the two published octopine virB sequences with the nopaline sequence presented here is made.

AB - Agrobacterium tumefaciens genetically transforms plant cells by transferring a copy of its T-DNA to the plant where it is integrated and stably maintained. In the presence of wounded plant cells this process is activated and mediated by the products of the vir genes which are grouped into six distinct loci. The largest is the virB locus spanning 9.5 kb. Transposon mutagenesis studies have shown that virB gene products are required for virulence but their functions remain largely unknown. To provide information relevant to understanding the function of VirB polypeptides, the nucleotide sequence of the virB operon from a nopaline plasmid, pTiC58, is presented here. Eleven open reading frames (ORFs) are predicted from this sequence. The predicted sizes of 10 of the 11 VirB polypeptides are verified by specific expression in Escherichia coli. Only the product of the smallest ORF potentially encoding a 5.8 kDa polypeptide has not been detected. The initiation of translation of five virB ORFs occurs at codons that overlap the termination codons of the ORF immediately upstream; thus, translational coupling may be an important mechanism for efficient translation of the large virB polycistronic mRNA. Based on hydropathy plot analysis nine of the virB ORFs encode proteins that may interact with membranes; these data support the earlier hypothesis (Engstromm et al. 1987) that virB gene products may form a membrane pore or channel to mediate exit of the T-DNA copy (T-strands) from Agrobacterium into the plant cell. A comparison of the two published octopine virB sequences with the nopaline sequence presented here is made.

UR - http://www.scopus.com/inward/record.url?scp=0025355447&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0025355447&partnerID=8YFLogxK

U2 - 10.1007/BF00261729

DO - 10.1007/BF00261729

M3 - Article

C2 - 2370849

AN - SCOPUS:0025355447

VL - 221

SP - 256

EP - 266

JO - Molecular Genetics and Genomics

JF - Molecular Genetics and Genomics

SN - 1617-4615

IS - 2

ER -