TY  - JOUR
A1  - Nguyen, Hung M.
A1  - Schippers, Jos H. M.
A1  - Goni-Ramos, Oscar
A1  - Christoph, Mathias P.
A1  - Dortay, Hakan
A1  - van der Hoorn, Renier A. L.
A1  - Müller-Röber, Bernd
T1  - An upstream regulator of the 26S proteasome modulates organ size in Arabidopsis thaliana
JF  - The plant journal
N2  - In both animal and plant kingdoms, body size is a fundamental but still poorly understood attribute of biological systems. Here we report that the Arabidopsis NAC transcription factor Regulator of Proteasomal Gene Expression' (RPX) controls leaf size by positively modulating proteasome activity. We further show that the cis-element recognized by RPX is evolutionarily conserved between higher plant species. Upon over-expression of RPX, plants exhibit reduced growth, which may be reversed by a low concentration of the pharmacological proteasome inhibitor MG132. These data suggest that the rate of protein turnover during growth is a critical parameter for determining final organ size.
KW  - Arabidopsis thaliana
KW  - organ size
KW  - evolution
KW  - leaf development
KW  - proteasome
KW  - gene regulatory network
Y1  - 2013
U6  - https://doi.org/10.1111/tpj.12097
SN  - 0960-7412
VL  - 74
IS  - 1
SP  - 25
EP  - 36
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Matallana-Ramirez, Lilian P.
A1  - Rauf, Mamoona
A1  - Farage-Barhom, Sarit
A1  - Dortay, Hakan
A1  - Xue, Gang-Ping
A1  - Droege-Laser, Wolfgang
A1  - Lers, Amnon
A1  - Balazadeh, Salma
A1  - Müller-Röber, Bernd
T1  - NAC Transcription Factor ORE1 and Senescence-Induced BIFUNCTIONAL NUCLEASE1 (BFN1) Constitute a Regulatory Cascade in Arabidopsis
JF  - Molecular plant
N2  - The NAC transcription factor ORE1 is a key regulator of senescence in Arabidopsis thaliana. Here, we demonstrate that senescence-induced and cell death-associated BIFUNCTIONAL NUCLEASE1 (BFN1) is a direct downstream target of ORE1, revealing a previously unknown regulatory cascade.Senescence is a highly regulated process that involves the action of a large number of transcription factors. The NAC transcription factor ORE1 (ANAC092) has recently been shown to play a critical role in positively controlling senescence in Arabidopsis thaliana; however, no direct target gene through which it exerts its molecular function has been identified previously. Here, we report that BIFUNCTIONAL NUCLEASE1 (BFN1), a well-known senescence-enhanced gene, is directly regulated by ORE1. We detected elevated expression of BFN1 already 2 h after induction of ORE1 in estradiol-inducible ORE1 overexpression lines and 6 h after transfection of Arabidopsis mesophyll cell protoplasts with a 35S:ORE1 construct. ORE1 and BFN1 expression patterns largely overlap, as shown by promoterreporter gene (GUS) fusions, while BFN1 expression in senescent leaves and the abscission zones of maturing flower organs was virtually absent in ore1 mutant background. In vitro binding site assays revealed a bipartite ORE1 binding site, similar to that of ORS1, a paralog of ORE1. A bipartite ORE1 binding site was identified in the BFN1 promoter; mutating the cis-element within the context of the full-length BFN1 promoter drastically reduced ORE1-mediated transactivation capacity in transiently transfected Arabidopsis mesophyll cell protoplasts. Furthermore, chromatin immunoprecipitation (ChIP) demonstrates in vivo binding of ORE1 to the BFN1 promoter. We also demonstrate binding of ORE1 in vivo to the promoters of two other senescence-associated genes, namely SAG29/SWEET15 and SINA1, supporting the central role of ORE1 during senescence.
KW  - Arabidopsis thaliana
KW  - senescence
KW  - transcription factor
KW  - ORE1
KW  - BFN1
KW  - promoter
Y1  - 2013
U6  - https://doi.org/10.1093/mp/sst012
SN  - 1674-2052
VL  - 6
IS  - 5
SP  - 1438
EP  - 1452
PB  - Oxford Univ. Press
CY  - Oxford
ER  -