Identification of cis -regulatory sequences that activate transcription in the suspensor of plant embryos

Abstract

Little is known about the molecular mechanisms by which the embryo proper and suspensor of plant embryos activate specific gene sets shortly after fertilization. We analyzed the upstream region of the scarlet runner bean (Phaseolus coccineus) G564 gene to understand how genes are activated specifically within the suspensor during early embryo development. Previously, we showed that the G564 upstream region has a block of tandem repeats, which contain a conserved 10-bp motif (GAAAAG C /TGAA), and that deletion of these repeats results in a loss of suspensor transcription. Here, we use gain-of-function (GOF) experiments with transgenic globular-stage tobacco embryos to show that only 1 of the 5 tandem repeats is required to drive suspensor-specific transcription. Fine-scale deletion and scanning mutagenesis experiments with 1 tandem repeat uncovered a 54-bp region that contains all of the sequences required to activate transcription in the suspensor, including the 10-bp motif (GAAAAGCGAA) and a similar 10-bp-like motif (GAAAAACGAA). Site-directed mutagenesis and GOF experiments indicated that both the 10-bp and 10-bp-like motifs are necessary, but not sufficient to activate transcription in the suspensor, and that a sequence (TTGGT) between the 10-bp and the 10-bp-like motifs is also necessary for suspensor transcription. Together, these data identify sequences that are required to activate transcription in the suspensor of a plant embryo after fertilization.promoter analysis ͉ scarlet runner bean

Three Sequenced Legume Genomes and Many Crop Species: Rich Opportunities for Translational Genomics

“…Common bean has been used to characterize the molecular basis of photoperiod sensitivity and determinacy (Kwak et al, 2008). Scarlet runner bean (Phaseolus coccineus), with its very-large seeds, has been developed as a model to study embryo and seed development (Kawashima et al, 2009). The mimosoid legume Mimosa pudica (the sensitive plant), whose leaves and petioles respond to touch by closing (thigmonasty), have been studied to determine the basis for their rapid responses (Uehlein and Kaldenhoff, 2008).…”

Global analysis of gene activity duringArabidopsisseed development and identification of seed-specific transcription factors

“…Genetic studies with Arabidopsis have uncovered several genes that play major roles in seed development (9)(10)(11), including those that govern endosperm formation (12,13), embryo differentiation (14,15), and seed coat development (8). In addition, molecular studies with Arabidopsis and other plants have identified the ciscontrol regions of several genes active during seed development, particularly those encoding storage proteins, and the transcription factors (TFs) that play a role in their regulation (16)(17)(18)(19)(20)(21)(22). Nevertheless, the identities of most regulators of seed development and their direct targets are largely unknown.…”

Thousands of Cis-Regulatory Sequence Combinations Are Shared by Arabidopsis and Poplar

“…Many experimental CRM studies in plants consider cooccurrence of TFBSs of individual TFs with multiple DNA binding domains or a pair of interacting TFs (Solano et al, 1995;Chen et al, 1996;Singh, 1998;Kagaya et al, 1999;Nagano et al, 2001;Abe et al, 2003;Konishi and Yanagisawa, 2010), although a plant CRM may consist of TFBSs of three or more TFs (Baudry et al, 2004;Kim et al, 2004;Akyildiz et al, 2007;Kawashima et al, 2009;Wang et al, 2010). In addition, these studies often identify only individual CRMs for individual genes, and only consider a limited number of TFs (Steffens et al, 2005).…”