Activity of transcription factor JACKDAW is essential for SHR/SCR-dependent activation of SCARECROW and MAGPIE and is modulated by reciprocal interactions with MAGPIE, SCARECROW and SHORT ROOT

Abstract

Two GRAS family transcription factors, SHORT-ROOT (SHR) and SCARECROW (SCR), are required for ground tissue and quiescent center formation in Arabidopsis roots. The action of SHR and SCR is regulated by two INDETERMINATE DOMAIN (IDD) family proteins, JACKDAW (JKD) and MAGPIE (MGP). Although the reciprocal interaction of these transcription factors is considered to be involved in the modulation of SHR and SCR action by JKD and MGP, the underlying mechanism remains unclear. In this study, we use a transient assay with Arabidopsis culture cells to show that the physical interaction of these transcription factors modulate their transcriptional activity. Transient expression of LUC reporter genes with the proximal sequences upstream from the ATG codon of SCR and MGP in protoplasts were activated by JKD. Moreover, promoter activities were enhanced further by the addition of SHR and SCR to JKD, but not by the combination of SHR and SCR in the absence of JKD. Yeast one-hybrid analysis showed that JKD binds to the SCR and MGP promoter sequences, indicating the existence of another binding sequences of JKD different from the previously determined IDD binding sequence. Our findings suggest that JKD directly regulates SCR and MGP expression in cooperation with SHR, SCR and MGP.

Thenaked endospermGenes Encode Duplicate INDETERMINATE Domain Transcription Factors Required for Maize Endosperm Cell Patterning and Differentiation

“…JACKDAW and MAGPIE act downstream of SHORTROOT and SCARECROW in establishing radial pattern and cell identities in the root apex (Welch et al, 2007;Hassan et al, 2010;Ogasawara et al, 2011). IDD4 and several other IDD genes are direct targets of regulation by REVOLUTA and KANADI, implicated in establishing the adaxial/abaxial pattern and cell fates in leaves and other lateral organs (Reinhart et al, 2013).…”

Medicago truncatula ERN Transcription Factors: Regulatory Interplay with NSP1/NSP2 GRAS Factors and Expression Dynamics throughout Rhizobial Infection

“…Chromatin immunoprecipitation provided evidence for the association in vivo of other GRAS proteins with promoters of their putative target genes, such as DELLA (Zentella et al, 2007) and SHORTROOT (SHR;Cui et al, 2007). Although a role in the transcriptional regulation of their putative targets has been reported for other GRAS factors, in most cases they seem to act as coactivators (Morohashi et al, 2003;Ogasawara et al, 2011). As for NSP1 and NSP2, SHR and SCARECROW (SCR) GRAS TFs are unable to significantly activate transcription without associating with other TFs.…”

Arabidopsis BIRD Zinc Finger Proteins Jointly Stabilize Tissue Boundaries by Confining the Cell Fate Regulator SHORT-ROOT and Contributing to Fate Specification

“…To quantify the effect of BIRD proteins in retaining nuclear SHR, we measured nuclear and cytoplasmic SHR-YFP fluorescence intensity in the vasculature with ectopic SCR or BIRD proteins expression and found that in the roots, the presence of BIRD proteins enhanced SHR nuclear portion to similar levels as SCR (Supplemental Figure 6F). As JKD is required to activate SCR expression (Ogasawara et al, 2011), we tested whether SHR nuclear localization mediated by JKD and BIB operated in part through induction of SCR. We first analyzed SCR expression in lines misexpressing JKD and BIB in the vascular domain and found that SCR was ectopically induced in the vascular tissue ( Figures 3F to 3I').…”