Gene_locus Report for: orysa-gid1

Gibberellins (GAs) are phytohormones essential for many developmental processes in plants. A nuclear GA receptor, GIBBERELLIN INSENSITIVE DWARF1 (GID1), has a primary structure similar to that of the hormone-sensitive lipases (HSLs). Here we analyse the crystal structure of Oryza sativa GID1 (OsGID1) bound with GA(4) and GA(3) at 1.9 A resolution. The overall structure of both complexes shows an alpha/beta-hydrolase fold similar to that of HSLs except for an amino-terminal lid. The GA-binding pocket corresponds to the substrate-binding site of HSLs. On the basis of the OsGID1 structure, we mutagenized important residues for GA binding and examined their binding activities. Almost all of them showed very little or no activity, confirming that the residues revealed by structural analysis are important for GA binding. The replacement of Ile 133 with Leu or Val-residues corresponding to those of the lycophyte Selaginella moellendorffii GID1s-caused an increase in the binding affinity for GA(34), a 2beta-hydroxylated GA(4). These observations indicate that GID1 originated from HSL and was further modified to have higher affinity and more strict selectivity for bioactive GAs by adapting the amino acids involved in GA binding in the course of plant evolution.

A fine physical map of the rice (Oryza sativa spp. Japonica var. Nipponbare) chromosome 5 with bacterial artificial chromosome (BAC) and PI-derived artificial chromosome (PAC) clones was constructed through integration of 280 sequenced BAC/PAC clones and 232 sequence tagged site/expressed sequence tag markers with the use of fingerprinted contig data of the Nipponbare genome. This map consists of five contigs covering 99% of the estimated chromosome size (30.08 Mb). The four physical gaps were estimated at 30 and 20 kb for gaps 1-3 and gap 4, respectively. We have submitted 42.2-Mb sequences with 29.8 Mb of nonoverlapping sequences to public databases. BAC clones corresponding to telomere and centromere regions were confirmed by BAC-fluorescence in situ hybridization (FISH) on a pachytene chromosome. The genetically centromeric region at 54.6 cM was covered by a minimum tiling path spanning 2.1 Mb with no physical gaps. The precise position of the centromere was revealed by using three overlapping BAC/PACs for approximately 150 kb. In addition, FISH results revealed uneven chromatin condensation around the centromeric region at the pachytene stage. This map is of use for positional cloning and further characterization of the rice functional genomics.

Gibberellins (GAs) are phytohormones that are essential for many developmental processes in plants. It has been postulated that plants have both membrane-bound and soluble GA receptors; however, no GA receptors have yet been identified. Here we report the isolation and characterization of a new GA-insensitive dwarf mutant of rice, gid1. The GID1 gene encodes an unknown protein with similarity to the hormone-sensitive lipases, and we observed preferential localization of a GID1-green fluorescent protein (GFP) signal in nuclei. Recombinant glutathione S-transferase (GST)-GID1 had a high affinity only for biologically active GAs, whereas mutated GST-GID1 corresponding to three gid1 alleles had no GA-binding affinity. The dissociation constant for GA4 was estimated to be around 10(-7) M, enough to account for the GA dependency of shoot elongation. Moreover, GID1 bound to SLR1, a rice DELLA protein, in a GA-dependent manner in yeast cells. GID1 overexpression resulted in a GA-hypersensitive phenotype. Together, our results indicate that GID1 is a soluble receptor mediating GA signalling in rice.

Gibberellins (GAs) are tetracyclic, diterpenoid plant hormones, essential for many developmental processes in higher plants. Plants perceive GA through a nuclear-localized GA receptor, GA INSENSITIVE DWARF1 (GID1). From sequence similarity, it is suggested that GID1 evolved from a hormone-sensitive lipase (HSL), and recent x-ray crystallography of the GA-GID1 complex has given insights into how GID1 recognizes GA. Analyses of the GA signaling pathway in several plant species further suggest that the GID1-mediated GA signaling pathway emerged in the vascular plant lineage and since then regulation of GA recognition specificity seems to have been fine tuned to strictly regulate the on-off GA signal.

Gibberellins (GAs) are phytohormones essential for many developmental processes in plants. A nuclear GA receptor, GIBBERELLIN INSENSITIVE DWARF1 (GID1), has a primary structure similar to that of the hormone-sensitive lipases (HSLs). Here we analyse the crystal structure of Oryza sativa GID1 (OsGID1) bound with GA(4) and GA(3) at 1.9 A resolution. The overall structure of both complexes shows an alpha/beta-hydrolase fold similar to that of HSLs except for an amino-terminal lid. The GA-binding pocket corresponds to the substrate-binding site of HSLs. On the basis of the OsGID1 structure, we mutagenized important residues for GA binding and examined their binding activities. Almost all of them showed very little or no activity, confirming that the residues revealed by structural analysis are important for GA binding. The replacement of Ile 133 with Leu or Val-residues corresponding to those of the lycophyte Selaginella moellendorffii GID1s-caused an increase in the binding affinity for GA(34), a 2beta-hydroxylated GA(4). These observations indicate that GID1 originated from HSL and was further modified to have higher affinity and more strict selectivity for bioactive GAs by adapting the amino acids involved in GA binding in the course of plant evolution.

A fine physical map of the rice (Oryza sativa spp. Japonica var. Nipponbare) chromosome 5 with bacterial artificial chromosome (BAC) and PI-derived artificial chromosome (PAC) clones was constructed through integration of 280 sequenced BAC/PAC clones and 232 sequence tagged site/expressed sequence tag markers with the use of fingerprinted contig data of the Nipponbare genome. This map consists of five contigs covering 99% of the estimated chromosome size (30.08 Mb). The four physical gaps were estimated at 30 and 20 kb for gaps 1-3 and gap 4, respectively. We have submitted 42.2-Mb sequences with 29.8 Mb of nonoverlapping sequences to public databases. BAC clones corresponding to telomere and centromere regions were confirmed by BAC-fluorescence in situ hybridization (FISH) on a pachytene chromosome. The genetically centromeric region at 54.6 cM was covered by a minimum tiling path spanning 2.1 Mb with no physical gaps. The precise position of the centromere was revealed by using three overlapping BAC/PACs for approximately 150 kb. In addition, FISH results revealed uneven chromatin condensation around the centromeric region at the pachytene stage. This map is of use for positional cloning and further characterization of the rice functional genomics.

Gibberellins (GAs) are phytohormones that are essential for many developmental processes in plants. It has been postulated that plants have both membrane-bound and soluble GA receptors; however, no GA receptors have yet been identified. Here we report the isolation and characterization of a new GA-insensitive dwarf mutant of rice, gid1. The GID1 gene encodes an unknown protein with similarity to the hormone-sensitive lipases, and we observed preferential localization of a GID1-green fluorescent protein (GFP) signal in nuclei. Recombinant glutathione S-transferase (GST)-GID1 had a high affinity only for biologically active GAs, whereas mutated GST-GID1 corresponding to three gid1 alleles had no GA-binding affinity. The dissociation constant for GA4 was estimated to be around 10(-7) M, enough to account for the GA dependency of shoot elongation. Moreover, GID1 bound to SLR1, a rice DELLA protein, in a GA-dependent manner in yeast cells. GID1 overexpression resulted in a GA-hypersensitive phenotype. Together, our results indicate that GID1 is a soluble receptor mediating GA signalling in rice.