The cap structure and the poly(A) tail are important regulatory determinants in establishing translational efficiency of a messenger RNA. Although mechanism by which either determinant functions remains poorly characterized, interaction between tail-poly(A)-binding protein complex events occurring at 5' terminus during translation initiation has been an intriguing possibility. In this report, mutual dependence was studied. Poly(A)+ poly(A)- luciferase (Luc) mRNAs generated vitro containing...

Vitamin C (ascorbic acid) is essential to prevent disease associated with connective tissue (e.g., scurvy), improves cardiovascular and immune cell functions, used regenerate alpha-tocopherol (vitamin E). In contrast most animals, humans lack the ability synthesize ascorbic acid as a result of mutation in last enzyme required for ascorbate biosynthesis. C, therefore, must be obtained from dietary sources and, because it cannot stored body, regularly. Once used, can regenerated its oxidized...

A 67-nucleotide portion of the non-coding, 5′-leader sequence tobacco mosaic virus RNA [defined as Ω' (Gr. omega prime)] has been shown to enhance translation contiguous foreign gene transcripts both in vitro and vivo. Chemically-synthesized Ω', containing convenient linker sequences, was inserted into derivatives an transcription plasmid (pSP64) between bacteriophage-SP6 promoter sequences coding for either chloramphenicol acetyltransferase (CAT) or neomycin phosphotransferase (NPTII)....

H(2)O(2) serves an important stress signaling function and promotes stomatal closure, whereas ascorbic acid (Asc) is the major antioxidant that scavenges H(2)O(2). Dehydroascorbate reductase (DHAR) catalyzes reduction of dehydroascorbate (oxidized ascorbate) to Asc thus contributes regulation redox state. In this study, we observed level state in guard cells whole leaves are diurnally regulated such former increases during afternoon, latter decreases. Plants with increased cell were...

We characterized the progression of programmed cell death during maize (Zea mays L.) endosperm development starchy (Su; wild-type) and shrunken2 (sh2) genotypes tested involve ment ethylene in mediating this process. Histological viability staining demonstrated that was initiated earlier progressed more rapidly sh2 compared with Su endosperm. Internucleosomal DNA fragmentation accompanied occurred extensively 1-Aminocyclopropane-1-carboxylic acid levels peaked approximately 16 d after...

The 5′-cap and the poly(A) tail act synergistically to increase translational efficiency of eukaryotic mRNAs, which suggests that these two mRNA elements communicate during translation. We report here cap-associated initiation factors (eIFs), <i>i.e.</i> isoforms cap-binding complex (eIF-4F eIF-iso4F) eIF-4B, bind poly(A)-binding protein (PABP) both in presence absence RNA. interactions between PABP eIF-4F, eIF-iso4F, eIF-4B were measured RNA using far Western analysis confirmed by direct...

Abstract Ascorbic acid (Asc) is a major antioxidant in plants that detoxifies reactive oxygen species (ROS) and maintains photosynthetic function. Expression of dehydroascorbate reductase (DHAR), responsible for regenerating Asc from an oxidized state, regulates the cellular redox which turn affects cell responsiveness tolerance to environmental ROS. Because its role recycling, we examined whether DHAR important plant growth. Suppression expression resulted preferential loss chlorophyll a,...

Ascorbic acid (Asc) is the most abundant antioxidant in plants and serves as a major contributor to cell redox state. Exposure environmental ozone can cause significant damage by imposing conditions of oxidative stress. We examined whether increasing level Asc through enhanced recycling would limit deleterious effects Plants overexpressing dehydroascorbate reductase (DHAR), which results an increase endogenous Asc, were exposed acute or chronic levels ozone. DHAR-overexpressing had lower...

The leader (called Ω) of tobacco mosaic virus RNA enhances translation in both eukaryotes and prokaryotes. Although little secondary structure is predicted to exist within Ω, the primary sequence 68 base highly organized. Three copies an eight direct repeat a (CAA) n region represent two motifs found leaders many TMV strains, together these comprise 72% Ω. In previous deletion studies, no mutants exhibited loss-of-function, suggesting that functional redundancy exists We report here more...

Summary In addition to their essential role in plant development, brassinosteroids have the ability protect plants from various environmental stresses. Currently it is not understood how control stress responses at molecular level. We begun an investigation into mechanisms underlying 24‐epibrassinolide (EBR)‐mediated resistance. Earlier we found that treatment of Brassica napus seedlings with EBR leads a significant increase basic thermotolerance, and results higher accumulation four major...

The 5′-untranslated leader, sequences of several plant RNA viruses, and a portion the 5′-leader an animal retrovirus, were tested for their ability to enhance expression contiguous open reading frames chloramphenicol acetyltransferase (CAT) or β-glucuronidase (GUS) in tobacco mesophyll protoplasts, Escherichia coli oocytes Xenopus laevis . Translation capped uncapped transcripts was substantially enhanced almost all systems by leader sequence either U1 SPS strain TMV. All sequences, except...

In this paper we demonstrate that RNA sequences present upstream and downstream of a reporter gene coding region play an important role in determining the amount protein produced from mRNA. A translational enhancer, omega, derived tobacco mosaic virus, when at 5'-end beta-glucuronidase mRNA increased efficiency translation 16-fold to 18-fold electroporated or carrot protoplasts, threefold 11-fold maize rice protoplasts. The presence omega did not alter half-life vivo. We also for first time...

All polyadenylated mRNAs contain sequence of variable length between the coding region and poly(A) tail. Little has been done to establish what role 3' untranslated (3'UTR) plays in posttranscriptional regulation. Using firefly luciferase (luc) reporter mRNA transiently transfected Chinese hamster ovary (CHO) cells, we observed that addition a tail increased expression 97-fold when 3'UTR was 19 bases but its stimulatory effect only 2.3-fold 156 bases. The luc on function orientation...

Crop loss due to soil salinization is an increasing threat agriculture worldwide. This review provides overview of cellular and physiological mechanisms in plant responses salt. We place a time- tissue-dependent context ...Read More

Summary Ethylene regulates entry into several types of plant developmental cell death and senescence programs besides mediating responses to biotic abiotic stress. The response cereals conditions drought includes loss leaf function premature onset in older leaves. In this study, ACC synthase ( ACS ) mutants, affecting the first step ethylene biosynthesis, were isolated maize their effect on examined. Loss ZmACS6 expression resulted delayed under normal growth inhibited drought‐induced...

Eukaryotic initiation factor (eIF) 4G plays an important role in assembling the complex required for ribosome binding to mRNA. Plants, animals, and yeast each express two eIF4G homologs, which share only 30, 46, 53% identity, respectively. We have examined functional differences between plant proteins, referred as eIFiso4G, when present subunits of eIF4F eIFiso4F, The degree a 5′-cap stimulated translation was inversely correlated with concentration or eIFiso4F poly(A)-binding protein...

Both the 68-base 5' leader (omega) and 205-base 3' untranslated region (UTR) of tobacco mosaic virus (TMV) promote efficient translation. A 35-base within omega is necessary sufficient for regulation. Within UTR, a 52-base region, composed two RNA pseudoknots, required These pseudoknots are phylogenetically conserved among seven viruses from different viral groups one satellite virus. The contained significant conservation at secondary tertiary levels several positions primary sequence...

The genomes of many RNA viruses terminate in a tertiary structure similar to the L-conformation tRNAs and this is recognized by tRNA-specific enzymes such as aminoacyl-tRNA synthetase. Virtually entire 3'-untranslated region (UTR) tobacco mosaic virus (TMV) involved an extended containing, addition tRNA-like structure, pseudoknot domain that lies immediately upstream. Although functions these structures are not well understood, they essential virus. We demonstrate 204-base TMV foreign mRNA...

The 5′‐leader sequence (called Ω) of tobacco mosaic virus (TMV) functions as a translational enhancer in plants. A poly(CAA) region within Ω is responsible for the translation enhancement and serves binding site heat shock protein, HSP101, which required enhancement. Genetic analysis HSP101‐mediated from Ω‐containing mRNA suggested that two eukaryotic initiation factors (eIFs), i.e. eIF4G eIF3, were necessary. In this study, functional interaction between other RNA elements known to...

The 5' leader (Omega) of tobacco mosaic viral RNA functions as a translational enhancer. Sequence analysis 102-kD protein, identified previously specific Omega RNA-binding revealed homology to the HSP101/HSP104/ClpB family heat shock proteins and its expression in yeast complemented thermotolerance defect caused by deletion HSP104 gene. Up 50-fold increase translation Omega-luc, but not luc mRNA was observed expressing HSP101 whereas failed enhance absence HSP101. Therefore, comprise...