KNOTTED1-LIKE HOMEOBOX (KNOX) genes are important regulators of meristem function, and a complex network of transcription factors ensures tight control of their expression. Here, we show that members of the GROWTH-REGULATING FACTOR (GRF) family act as players in this network. A yeast (Saccharomyces cerevisiae) one-hybrid screen with the upstream sequence of the KNOX gene Oskn2 from rice (Oryza sativa) resulted in isolation of OsGRF3 and OsGRF10. Specific binding to a region in the untranslated leader sequence of Oskn2 was confirmed by yeast and in vitro binding assays. ProOskn2:β-glucuronidase reporter expression was down-regulated by OsGRF3 and OsGRF10 in vivo, suggesting that these proteins function as transcriptional repressors. Likewise, we found that the GRF protein BGRF1 from barley (Hordeum vulgare) could act as a repressor on an intron sequence in the KNOX gene Hooded/Barley Knotted3 (Bkn3) and that AtGRF4, AtGRF5, and AtGRF6 from Arabidopsis (Arabidopsis thaliana) could repress KNOTTED-LIKE FROM ARABIDOPSIS THALIANA2 (KNAT2) promoter activity. OsGRF overexpression phenotypes in rice were consistent with aberrant meristematic activity, showing reduced formation of tillers and internodes and extensive adventitious root/shoot formation on nodes. These effects were associated with down-regulation of endogenous Oskn2 expression by OsGRF3. Conversely, RNA interference silencing of OsGRF3, OsGRF4, and OsGRF5 resulted in dwarfism, delayed growth and inflorescence formation, and up-regulation of Oskn2. These data demonstrate conserved interactions between the GRF and KNOX families of transcription factors in both monocot and dicot plants.
Interaction between the GROWTH-REGULATING FACTOR and KNOTTED1-LIKE HOMEOBOX Families of Transcription Factors / S.J.Kuijt, R. Greco, A. Agalou, J. Shao, C.C. 't Hoen, E. Overnäs, M. Osnato,S. Curiale, D. Meynard, R. van Gulik, S. F. Maraschin, M. Atallah, R.J. de Kam, G.E. Lamers, E. Guiderdoni, L. Rossini, A.H. Meijer, P.B. Ouwerkerk. - In: PLANT PHYSIOLOGY. - ISSN 0032-0889. - 164:4(2014 Apr), pp. 1952-1966.
|Titolo:||Interaction between the GROWTH-REGULATING FACTOR and KNOTTED1-LIKE HOMEOBOX Families of Transcription Factors|
|Settore Scientifico Disciplinare:||Settore AGR/07 - Genetica Agraria|
|Data di pubblicazione:||apr-2014|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1104/pp.113.222836|
|Appare nelle tipologie:||01 - Articolo su periodico|