Keith Roberts

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Endoreduplication is a common process in eukaryotes that involves DNA amplification without corresponding cell divisions. Cell size in various organisms has been linked to endoreduplication, but the molecular mechanisms are poorly understood. We have used a genetic strategy to identify molecules involved in endocycles in Arabidopsis. We isolated two extreme(More)
The biosynthesis of plant cell wall polysaccharides requires the concerted action of nucleotide sugar interconversion enzymes, nucleotide sugar transporters, and glycosyl transferases. How cell wall synthesis in planta is regulated, however, remains unclear. The root epidermal bulger 1 (reb1) mutant in Arabidopsis thaliana is partially deficient in cell(More)
Five Arabidopsis thaliana genes that encode UDP-glucose 4-epimerase (UGE) and represent two ancient plant UGE clades might be involved in the regulation of cell wall carbohydrate biosynthesis. We tested this hypothesis in a genome-wide reverse genetic study. Despite significant contributions of each gene to total UGE activity, none was essential for normal(More)
BACKGROUND Cell elongation is mainly limited by the extensibility of the cell wall. Dicotyledonous primary (growing) cell walls contain cellulose, xyloglucan, pectin and proteins, but little is known about how each polymer class contributes to the cell wall mechanical properties that control extensibility. RESULTS We present evidence that the degree of(More)
A small number of plant growth regulators are involved in the control of cell expansion. Despite knowledge of some of their signal transduction cascades, surprisingly little is known of how basic cell expansion-related processes, such as cell wall biosynthesis, are affected during growth. The Arabidopsis (Arabidopsis thaliana) mutant root hair defective1(More)
BACKGROUND Hepcidin is a 25-residue peptide hormone crucial to iron homeostasis. It is essential to measure the concentration of hepcidin in cells, tissues and body fluids to understand its mechanisms and roles in physiology and pathophysiology. With a mass of 2791 Da hepcidin is readily detectable by mass spectrometry and LC-ESI, MALDI and SELDI have been(More)
Office hours: By appointment only. Please see the TA if you need assistance with assignments or have questions about your grades. COURSE OBJECTIVES This is a 3-credit course designed for 1 st or 2 nd year graduate students. W ith a specific focus on newly emerging topics, t he molecular basis for the major intracellular signaling pathways of eukaryotes will(More)
This case demonstrates how hyperpigmentation of the nipple due to Paget's disease can imitate malignant melanoma presenting a diagnostic dilemma. A 62-year-old woman was referred by her GP to the West Sussex Breast Unit with a pigmented lesion on her left nipple that had been increasing in size for six months. She had recently moved back to the UK after(More)
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