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Articles 1 - 12 of 12

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

A Negative Regulator Of Ribosomal Rna Processing Specifies R-Gene-Independent Cell Death In Barley - Powdery Mildew Interactions, Liu Xi Jan 2008

A Negative Regulator Of Ribosomal Rna Processing Specifies R-Gene-Independent Cell Death In Barley - Powdery Mildew Interactions, Liu Xi

Retrospective Theses and Dissertations

Programmed Cell Death (PCD) plays a pivotal role in plant development and defense. Pathogen dependent cell-death mutants were used to investigate the complex regulatory pathways between PCD and R-gene mediated resistance. Time-course expression profiles of Blumeria graminis f. sp. hordei (Bgh) challenged C.I. 16151 (harboring the Mla6 powdery mildew resistance allele) and its fast-neutron-derived "Bgh-induced tip cell death1" mutant, bcd1, were compared using the 22K Barley1 GeneChip. Contrasts were made to identify genes associated with the cell death phenotype as opposed to R-gene mediated resistance. One hundred eighty-two genes were found in the intersection of these contrasts at a ...


Identification Of Stbel5 Rna As A Long-Distance Mobile Signal In Short-Day Facilitated Tuber Formation , Yueyue Yu Jan 2006

Identification Of Stbel5 Rna As A Long-Distance Mobile Signal In Short-Day Facilitated Tuber Formation , Yueyue Yu

Retrospective Theses and Dissertations

In potato, the BEL1-like transcription factor, StBEL5 and its protein partner POTH1, regulate tuber formation by mediating hormone levels in the stolon tip. Heterografting experiments show that StBEL5 mRNA can move across the graft union to localize in stolon tips and enhance tuber formation. Over-expression of StBEL5 full-length transcripts including the untranslated regions (UTRs) endows transgenic lines with the capacity to overcome the long-day inhibitory effects on tuber formation.;In this study, the precise localization of endogenous StBEL5 mRNA and other gene specific transcripts in the vascular tissues were determined by laser microdissection coupled to laser pressure catapulting (LMPC) and ...


Translational Control Of Gene Expression Mediated By The 3' Untranslated Region Of Barley Yellow Dwarf Virus , Elizabeth Lynn Pettit Jan 2005

Translational Control Of Gene Expression Mediated By The 3' Untranslated Region Of Barley Yellow Dwarf Virus , Elizabeth Lynn Pettit

Retrospective Theses and Dissertations

The 869 nt 3' untranslated region (3' UTR) of Barley yellow dwarf luteovirus (BYDV) RNA facilitates cap-independent and poly(A) tail-independent translation. A 105 nt cap-independent translation element (BTE, or BYDV TE) within the 3' UTR was previously defined using wheat germ translation extracts (Guo et al., 2000), but additional 3' UTR sequence is required for translation in plant cells. One domain, nt 4918--5008, confers cap-independent translation in vivo in a discrete and strong manner. Some of this extra sequence places the BTE on a phylogenetically conserved, long double-stranded "stalk", making it more accessible to cellular translational machinery. Another sequence ...


Sooty Blotch And Flyspeck On Apple: Expansion Of The Fungal Complex, Post-Harvest Removal And Heterogeneity Of Apple Canopy Wetness And Its Impact On The Outcome Of A Disease-Warning System , Jean Carlson Batzer Jan 2005

Sooty Blotch And Flyspeck On Apple: Expansion Of The Fungal Complex, Post-Harvest Removal And Heterogeneity Of Apple Canopy Wetness And Its Impact On The Outcome Of A Disease-Warning System , Jean Carlson Batzer

Retrospective Theses and Dissertations

Sooty blotch and flyspeck (SBFS) fungi blemish the cuticle of apples. Previous studies reported that the SBFS complex is comprised of four species. This is study surveyed the SBFS complex from nine orchards in four Midwestern states (USA). The LSU analyses of the rDNA inferred that 30 species were Dothideomycetes; one species was within the Pleosporales, 27 were within Dothideales, and two species could not be placed at the ordinal level. The LSU sequences of 17 Dothideales species clustered with LSU sequences of known species of Mycosphaerella. Post-harvest dips in commercial disinfestants were used to remove SBFS signs. Apples were ...


Gene Regulation Of Rna Viruses With Uncapped And Non-Polyadenylated Genomic Rna , Ruizhong Shen Jan 2004

Gene Regulation Of Rna Viruses With Uncapped And Non-Polyadenylated Genomic Rna , Ruizhong Shen

Retrospective Theses and Dissertations

New roles of RNAs as regulators of gene expression have emerged and expanded in recent years. However, gene regulation by viral RNA in trans is less noted and not well understood. Barley yellow dwarf virus (BYDV) is a positive sense RNA virus with a single genomic RNA (gRNA). As it replicates it generates three subgenomic RNAs (sgRNA). Data in this dissertation show that BYDV sgRNA2 serves as a regulatory RNA to control viral gene expression. In vitro and In vivo, BYDV sgRNA2 inhibits translation of gRNA, but has less or little effect on translation of sgRNA1, respectively. These data support ...


Molecular Mechanisms Of Cap And Poly(A) Independent Translation Of Barley Yellow Dwarf Virus Rna , Edwards M. Allen Jan 2001

Molecular Mechanisms Of Cap And Poly(A) Independent Translation Of Barley Yellow Dwarf Virus Rna , Edwards M. Allen

Retrospective Theses and Dissertations

Barley yellow dwarf virus RNA contains a translation element (3 'TE) that confers efficient cap-independent initiation at the 5 proximal AUG. Direct end-labeling of RNAs verified the absence of a 5 ' modification on virion RNA. Thus BYDV differs from related viruses by having neither a genome-linked protein nor a 5 ' cap. To function in the 3' UTR, the 3 'TE must recruit ribosomes and associated translation factors, and communicate with the 5' end of the mRNA where translation initiates. The communication function is mediated by direct base pairing between the 3'TE and the 5' UTR. We propose that protein ...


Structure And Function Of A Novel Cap-Independent Translation Element In The 3' Untranslated Region Of A Viral Rna , Liang Guo Jan 2000

Structure And Function Of A Novel Cap-Independent Translation Element In The 3' Untranslated Region Of A Viral Rna , Liang Guo

Retrospective Theses and Dissertations

This research focuses on a cap-independent translation element (TE) we identified in the RNA of barley yellow dwarf virus (BYDV). Assisted by the TE, all messenger RNAs of BYDV, which include BYDV genomic RNA and subgenomic RNAs, are translated cap-independently. This allows uncapped, nonpolyadenylated BYDV RNAs to compete with capped and polyadenylated host mRNAs for the translation machinery. The core of the TE is a 105 nt sequence (TE105) located in the 3' UTR of BYDV genomic RNA. Due to its 3' position, at least two functions are necessary for TE105: 3 '--5' communication, and recruitment of translation machinery. TE105 ...


Replication Of Barley Yellow Dwarf Virus Rna And Transcriptional Control Of Gene Expression , Guennadi Koev Jan 1999

Replication Of Barley Yellow Dwarf Virus Rna And Transcriptional Control Of Gene Expression , Guennadi Koev

Retrospective Theses and Dissertations

Barley yellow dwarf virus (BYDV) is an important pathogen of cereal crops. It has a single-stranded positive sense genomic RNA (gRNA), 5.7 kilobases. During infection of a plant cell, BYDV generates a nested set of three subgenomic mRNAs (sgRNAs) for expression of its 3'-proximal genes. The goal of this study was to map and characterize cis-acting RNA signals involved in transcription and replication of BYDV RNA. Three sgRNA promoters and the 3' origin of replication were characterized. The sgRNA1 promoter was mapped to a 98 nt region that contains two stem-loop structures. A combination of primary and secondary ...


The Poplar-Leaf Rust Pathosystem: Inheritance Of Resistance And Pathogenic Variability , Girma Melesse Tabor Jan 1998

The Poplar-Leaf Rust Pathosystem: Inheritance Of Resistance And Pathogenic Variability , Girma Melesse Tabor

Retrospective Theses and Dissertations

Among diseases that cause serious yield reduction on Populus deltoides is leaf rust caused by Melampsora medusae. The objectives of this project were to study the pathogenic variability of M. medusae, the genetic basis of inheritance of M. medusae resistance in a family of P. deltoides; and to identify molecular markers linked to a leaf-rust resistant locus. Three pathotypes of M. medusae were identified on the basis of their differential reaction to three Populus clones. Pathotypes D-93, F-93, and IL-48 were compatible with clone 1-488 (P. X euramericana). F-93 and IL48 were also compatible with clone 57-276 (P. deltoides X ...


Replication Of Barley Yellow Dwarf Luteovirus-Pav Rna , Mohan Bangalore Jan 1997

Replication Of Barley Yellow Dwarf Luteovirus-Pav Rna , Mohan Bangalore

Retrospective Theses and Dissertations

Barley yellow dwarf luteovirus (BYDV)-PAV serotype, an economically important virus of small grain cereals, has a positive-sense RNA genome encoding at least six open reading frames (ORFs). The goal of the research was to determine the genes and sequences involved in the viral replication and to design efficient antiviral strategies to BYDV-PAV. Genetically engineered resistance is essential for BYDV as the natural resistance is inadequate. Antiviral constructs such as sense RNA, antisense RNA and viral polymerase gene were tested for their ability to reduce virus titre in oat protoplasts as monitored by enzyme-linked immunosorbent assay. All antiviral constructs yielded ...


Biology Of Rpv Barley Yellow Dwarf Virus Satellite Rna , Lada Rasochova Jan 1996

Biology Of Rpv Barley Yellow Dwarf Virus Satellite Rna , Lada Rasochova

Retrospective Theses and Dissertations

Satellite RNAs (satRNAs) depend on their helper viruses for replication, encapsidation and spread. The goal of the research was to determine helper virus specificity and host range of the RPV barley yellow dwarf luteovirus (BYDV-RPV) satRNA (satRPV RNA) and assay satRPV RNA for the ability to affect the accumulation and modulate disease symptoms of its helper viruses in protoplasts and plants. Although similar in structural genes, subgroup I and II luteoviruses have very different polymerases. BYDV-RPV and beet western yellows virus (BWYV), members of subgroup II luteoviruses, supported satRPV RNA replication in monocotyledonous and dicotyledonous hosts, respectively. In contrast, BYDV-PAV ...


Regulation Of Translation By The 3' Untranslated Region Of Barley Yellow Dwarf Virus-Pav Rna , Shanping Wang Jan 1996

Regulation Of Translation By The 3' Untranslated Region Of Barley Yellow Dwarf Virus-Pav Rna , Shanping Wang

Retrospective Theses and Dissertations

Eukaryotic translation initiation is an important step for gene expression. This process is stimulated by the interaction of 5' cap and 3' poly(A) tail mediated by trans-acting factors. Positive sense viral RNA can differ from the cellular mRNA by lacking either a 5' cap, or 3' poly(A) tail or both. Therefore, various strategies have evolved by the RNA viruses to achieve efficient translation. Barley yellow dwarf virus-PAV serotype (BYDV-PAV) lacks both a 5' cap and 3' poly(A) tail. I found that a sequence (called 3'TE for 3' translation enhancer) at the 3'UTR of barley yellow ...