Untitled

Abstract

In mammalian cells the product of the human retinoblastoma tumour suppressor gene (pRb) can recruit Rpd3-like histone deacetylases to repress transcription. In this study, we investigated whether this mechanism might also be relevant in plants and found both conserved and distinct features. The expression profiles of the Zea mays Rpd3-type histone deacetylase (ZmRpd3I) and the retinoblastoma-related (ZmRBR1) homologues were analysed during endosperm development. GST pull-down and immunoprecipitation experiments showed a physical interaction between ZmRBRI and ZmRpd3I. Because ZmRpd3I lacks a LXCXE motif, conserved in several pRb-interacting proteins, we have mapped the amino acid domains involved in the ZmRBR1/ZmRpd3I interaction. Furthermore, we observed that ZmRbAp1, a maize member of the MSI/RbAp family, facilitated this protein interaction. Co-transformations of tobacco protoplasts with plasmids expressing ZmRBRI and ZmRpd3I showed that the two proteins cooperate in repressing gene transcription. Our findings represent the first indication that in plants a regulator of important biological processes, ZmRBRI, can recruit a histone deacetylase, ZmRpd3I, to control gene transcription.

Retinoblastoma and Its Binding Partner MSI1 Control Imprinting in Arabidopsis

“…We concluded that the interaction between MSI1 and RBR1 takes place in absence of the A/B pocket, suggesting that an HDAC1 is not involved in this interaction. In addition, the maize HDAC ZmRpd3I [35] and all Arabidopsis HDAC homologs do not contain the LxCxE domain, which is required for the interaction between Rb, HDAC1, and RbAp48 in mammals. In conclusion, we suggest that in contrast to mammals, the plant homologs of Rb and RbAp48 likely interact directly and may not require an HDAC1 homolog.…”

Looking at plant cell cycle from the chromatin window

“…RBR phosphorylation may abolish interaction with HDACs, favoring HAT activity that relieves gene repression (Rayman et al, 2002). Such balance has been demonstrated in several plant species (Ach et al, 1997; Nicolas et al, 2001; Rossi and Varotto, 2002; Rossi et al, 2003). …”

In silico analysis of protein Lys-N𝜀-acetylation in plants

“…Much like the KATs, the KDAC proteins display complex domain organization ( Figures 1B,D ), tissue-specific expression, and physiological functions. Members of the RPD3-like family are apparently present in all eukaryotes and have been the most widely studied KDACs (Murfett et al, 2001; Rossi et al, 2003). The HD-tuins appear to be present only in plants (Dangl et al, 2001; Luo et al, 2012) and have been the least studied.…”