Usha Vijayraghavan

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In this study we report the isolation of temperature-sensitive mutants that affect pre-mRNA splicing. A bank of approximately 1000 temperature-sensitive Saccharomyces cerevisiae strains was generated and screened on RNA gel blots by hybridization with an actin intron probe. We isolated 16 mutants defining 11 new complementation groups prp(rna)17-prp(rna)27(More)
Grass flowers are highly derived compared to their eudicot counterparts. To delineate OsMADS1 functions in rice floret organ development we have examined its evolution and the consequences of its knockdown or overexpression. Molecular phylogeny suggests the co-evolution of OsMADS1 with grass family diversification. OsMADS1 knockdown perturbs the(More)
MADS-domain-containing transcription factors play diverse roles in plant development. The prototypic members of this gene family are the floral organ identity genes of the model dicotyledonous plant, Arabidopsis thaliana. Sequence relatedness and function ascribe them to AP1/AGL9, AG, AP3 and PI gene groups. The rice MADS-box gene, OsMADS1, is a member of(More)
We report on the characterization of the yeast prp20-1 mutant. In this temperature-sensitive mutant, multiple steps of mRNA metabolism are affected. The prp20-1 mutant strain showed alterations in mRNA steady-state levels, defective mRNA splicing and changes in transcription initiation or termination when shifted from the permissive to the non-permissive(More)
We have isolated a yeast mutant, ts352, that is temperature-sensitive for growth. The mutation has a general effect on mRNA metabolism and a specific effect on tRNA biosynthesis. Cells shifted to the nonpermissive temperature accumulate tRNAs that are shorter than mature tRNAs. The increased ability of these tRNAs to accept ATP demonstrates that growth of(More)
Unlike many eudicot species, grasses have duplicated PI/GLO-like genes. Functional analysis of one of the rice PI/GLO paralogs, OsMADS2, is reported here. Our data demonstrate its essential role in lodicule development and implicate the second PI/GLO paralog, OsMADS4, to suffice for stamen specification. We provide the first evidence for differential(More)
SEPALLATA (SEP) MADS box transcription factors mediate floral development in association with other regulators. Mutants in five rice (Oryza sativa) SEP genes suggest both redundant and unique functions in panicle branching and floret development. leafy hull sterile1/OsMADS1, from a grass-specific subgroup of LOFSEP genes, is required for specifying a single(More)
Activity of axillary meristems dictates the architecture of both vegetative and reproductive parts of a plant. In Arabidopsis thaliana, a model eudicot species, the transcription factor LFY confers a floral fate to new meristems arising from the periphery of the reproductive shoot apex. Diverse orthologous LFY genes regulate vegetative-to-reproductive phase(More)
Yeast introns contain three highly conserved sequences which are known to be required for splicing of pre-mRNA. Using in vitro mutagenesis, we have synthesized seven point mutations at five different sites in these signals in the yeast actin intron. The mutant introns were then inserted into each of three constructs, which allowed us to assess the(More)
Studies of floral organ development in two dicotyledonous plants, Arabidopsis thaliana and Antirrhinum majus, have shown that three sets of genes (A, B and C) can pattern sepals, petals, stamens and carpels [1] [2]. Mechanisms that define boundaries between these floral whorls are unclear, however. The Arabidopsis gene SUPERMAN (SUP), which encodes a(More)