<i>Agrobacterium</i> transcriptional regulator Ros is a prokaryotic zinc finger protein that regulates the plant oncogene <i>ipt</i>

Proceedings of the National Academy of Sciences of the United States of America - Tập 95 Số 9 - Trang 5293-5298 - 1998
Alan Y. Chou1, John Archdeacon2,3, Clarence I. Kado2,3
1Davis Crown Gall Group University of California, Davis CA 95616, USA
2Davis Crown Gall Group, University of California, Davis, CA 95616
3University of California, Davis, CA

Tóm tắt

Virulence genes of Agrobacterium tumefaciens are under the control of positive and negative transcriptional regulators. We found that the transcriptional regulator Ros controls expression of the plant oncogene ipt , which encodes isopentenyl transferase, in A. tumefaciens . This enzyme is involved in biosynthesis of the plant growth hormone cytokinin in the host plant. An ipt promoter∷ cat reporter gene fusion showed a 10-fold increase in ipt promoter activity in A. tumefaciens ros mutant strains when compared with wild type. Also, increased levels (10- to 20-fold) of isopentenyl adenosine, the product of the reaction catalyzed by isopentenyl transferase, were detected in ros mutant strains. In vitro studies using purified Ros showed it binds directly to the ipt promoter. Analysis of the deduced Ros amino acid sequence identified a novel type of C 2 H 2 zinc finger. In Ros the peptide loop spacing of the zinc finger is 9 amino acids as opposed to the invariant 12 amino acids in the classical C 2 H 2 motif. Site-directed mutagenesis of Cys-82 and His-92 in this motif showed that these residues are essential for Zn 2+ and DNA binding activities of Ros. The existence of such a regulator in Agrobacterium may be due to horizontal interkingdom retrotransfer of the ros gene from plant to bacteria.

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Tài liệu tham khảo

10.1146/annurev.pp.37.060186.002453

10.1016/0147-619X(90)90028-B

10.1007/978-94-011-0746-4_15

B Tinland, B Hohn Virus Strategies, Molecular Biology and Pathogenesis, eds W Doerfler, P Böhm (VCH, Berlin), pp. 349–359 (1995).

10.1146/annurev.py.32.090194.001105

10.1146/annurev.pp.43.060192.002341

10.1128/mr.56.1.12-31.1992

10.1128/jb.169.11.5113-5118.1987

10.1128/jb.164.2.774-781.1985

10.1111/j.1365-2958.1988.tb00043.x

10.1128/jb.175.11.3486-3490.1993

10.1128/jb.173.8.2608-2616.1991

10.1094/MPMI-8-0747

10.1099/00221287-142-9-2621

10.1094/MPMI.1997.10.2.180

10.1094/MPMI-8-0267

10.1007/s004380050448

10.1094/MPMI.1997.10.5.550

10.1126/science.271.5252.1081

10.1038/nsb0694-345

10.1016/0092-8674(84)90455-0

10.1002/j.1460-2075.1985.tb03825.x

10.1038/320283a0

10.1093/nar/18.24.7433

10.1016/0076-6879(90)85008-C

10.1016/S0021-9258(19)74375-0

10.1016/0076-6879(75)43141-X

10.1016/S0048-4059(72)80002-X

10.1073/pnas.71.9.3672

10.1016/0968-0004(87)90231-3

10.1002/j.1460-2075.1985.tb03710.x

10.1146/annurev.pp.45.060194.001133

10.1093/nar/12.11.4665

10.1007/BF00330044

10.1073/pnas.86.7.2133

10.1038/scientificamerican0293-56

10.1016/0092-8674(87)90594-0

10.1002/j.1460-2075.1992.tb05047.x

H Takatsuji, N Nakamura, Y Katsumoto Plant Cell 6, 947–958 (1994).

10.1111/j.1432-1033.1993.tb18336.x

10.1007/BF00020246

10.1111/j.1365-2958.1995.tb02365.x

10.1093/nar/12.1Part1.387

10.1094/MPMI.1997.10.9.1087

10.1016/0168-9525(91)90433-Q

10.1128/jb.175.3.583-588.1993

10.1007/BF00023599

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Proceedings of the National Academy of Sciences of the United States of America

Tập 95 Số 9

5293-5298

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