A new family of cytokinin receptors from Cereales.
The highly specific recognition of a natural cytokinin, trans-zeatin, by cytokinin-binding protein (CBP) of 67 kDa from barley leaves was detected with an assay developed on the basis of cytokinin competition in ELISA with anti-idiotype antibodies (raised against antibodies to zeatin) for complex formation with CBP. Monoclonal antibodies (mAbs) raised against 70 kDa CBP from etiolated maize seedlings cross-reacted with barley 67 kDa CBP and prevented barley CBP and trans-zeatin induced activation of transcription elongation directed by RNA polymerase I associated with barley chromatin. One mAb (Z-6) had an agonistic effect. Maize CBP replaced barley CBP in activation of RNA synthesis with cytokinin in the barley transcription system. Hence, a new family of cytokinin receptors with common functions and immunodeterminants including maize and barley CBPs was found.
Kulaeva
O N
ON
Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow. vladimir@ad.plantphys.msk.ru
Zagranichnaya
T K
TK
Brovko
F A
FA
Karavaiko
N N
NN
Selivankina
S Y
SY
Zemlyachenko
Y V
YV
Hall
M
M
Lipkin
V M
VM
Boziev
K M
KM
D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D029681:Arabidopsis Proteins; D002352:Carrier Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D002843:Chromatin / Q000235:genetics; D003583:Cytokinins; D001467:Hordeum / Q000737:chemistry*; D010940:Plant Proteins; D012318:RNA Polymerase I / Q000378:metabolism*; D014158:Transcription, Genetic; D003313:Zea mays / Q000737:chemistry*
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D002843:Chromatin; D003583:Cytokinins; D010940:Plant Proteins; D012318:RNA Polymerase I