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Messenger RNA Transcripts (messenger + rna_transcript)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

A microarray's view of life in the desert: adding a powerful evolutionary genomics tool to the packrat's midden

MOLECULAR ECOLOGY, Issue 11 2009
MARJORIE D MATOCQ
Identifying the genetic architecture of adaptive traits is fundamental to understanding how organisms respond to their environment, over both ecological and evolutionary timeframes. Microarray technology that allows us to capture the simultaneous expression of thousands of genes provides unparalleled insight into how organisms cope with their environment at the transcriptional level. Recent studies in Molecular Ecology demonstrate how microarrays can rapidly identify which genes and pathways allow organisms to face some of the most fundamental physiological challenges posed by the environment, including compensation for the hypoxic and thermal stress of high-altitudes (Cheviron et al. 2008) and, in this issue, the biotransformation of toxic plant secondary compounds by mammals (Magnanou et al. 2009). Microarrays (Ekins et al. 1989; Fodor et al. 1991) are glass slides affixed with hundreds to thousands of oligonucleotide or cDNA sequences (probes). Messenger RNA transcripts (typically reverse transcribed to cDNA) are isolated from a tissue/sample of interest and hybridized to the array. Binding to specific probes indicates that a particular gene was transcriptionally active at or near the time of sampling and thus provides a potentially comprehensive measure of gene expression. Although a tremendously powerful tool, commercially produced oligonucleotide arrays are only available for a handful of model organisms. Nonetheless, evolutionary ecologists have exploited this resource by using a cross-species hybridization approach (e.g. Saetre et al. 2004), that is, hybridizing a model organism array with a nonmodel sample (Bar-Or et al. 2007). Magnanou et al. (2009) present a novel example of using a model muroid microarray (Agilent Technologies, Rattus) to study physiological response in a wild, nonmodel muroid, Neotoma. [source]

Multiple P2Y receptor subtypes in the apical membranes of polarized epithelial cells

BRITISH JOURNAL OF PHARMACOLOGY, Issue 8 2000
H L McAlroy
Apical ATP, ATP, UTP and UDP evoked transient increases in short circuit current (ISC, a direct measure of transepithelial ion transport) in confluent Caco-2 cells grown on permeable supports. These responses were mediated by a population of at least three pharmacologically distinct receptors. Experiments using cells grown on glass coverslips showed that ATP and UTP consistently increased intracellular free calcium ([Ca2+]i) whilst sensitivity to UDP was variable. Cross desensitization experiments suggested that the responses to UTP and ATP were mediated by a common receptor population. Messenger RNA transcripts corresponding to the P2Y2, P2Y4 and P2Y6 receptors genes were detected in cells grown on Transwell membranes by the reverse transcriptase,polymerase chain reaction. Identical results were obtained for cells grown on glass. Experiments in which ISC and [Ca2+]i were monitored simultaneously in cells on Transwell membranes, confirmed that apical ATP and UTP increased both parameters and showed that the UDP-evoked increase in ISC was accompanied by a [Ca2+]i -signal. Ionomycin consistently increased [Ca2+]i in such polarized cells but caused no discernible change in ISC. However, subsequent application of apical ATP or UTP evoked a small rise in ISC but no rise in [Ca2+]i. UDP evoked no such response. As well as evoking increases in [Ca2+]i, the ATP/UTP-sensitive receptors present in Caco-2 cells thus allow direct control over ion channels in the apical membrane. The UDP-sensitive receptors, however, appear to simply evoke a rise in [Ca2+]i. British Journal of Pharmacology (2000) 131, 1651,1658; doi:10.1038/sj.bjp.0703743 [source]

Translational read-through of a nonsense mutation in ATP7A impacts treatment outcome in Menkes disease,

ANNALS OF NEUROLOGY, Issue 1 2009
Stephen G. Kaler MPH
Protein translation ends when a stop codon in a gene's messenger RNA transcript enters the ribosomal A site. Mutations that create premature stop codons (nonsense mutations) typically cause premature translation termination. An alternative outcome, read-through translation (or nonsense suppression), is well known in prokaryotic, viral, and yeast genes but has not been clearly documented in humans except in the context of pharmacological manipulations. Here, we identify and characterize native read-through of a nonsense mutation (R201X) in the human copper transport gene, ATP7A. Western blotting, in vitro expression analyses, immunohistochemistry, and yeast complementation assays using cultured fibroblasts from a classic Menkes disease patient all indicated small amounts of native ATP7AR201X read-through and were associated with a dramatic clinical response to early copper treatment. Ann Neurol 2009;65:108,113 [source]

Expression of receptor activator of nuclear factor-,B ligand by B cells in response to oral bacteria

MOLECULAR ORAL MICROBIOLOGY, Issue 3 2009
X. Han
Introduction:, We investigated receptor activator of nuclear factor-,B ligand (RANKL) expression by B lymphocytes during early and late aspects of the immune response to Aggregatibacter actinomycetemcomitans, a gram-negative, anaerobic bacterium associated with aggressive periodontal disease. Methods:, Expression of messenger RNA transcripts (tumor necrosis factor-,, Toll-like receptors 4 and 9, interleukins 4 and 10, and RANKL) involved in early (1-day) and late (10-day) responses in cultured rat splenocytes was examined by reverse transcription,polymerase chain reaction (RT-PCR). The immune cell distribution (T, B, and natural killer cells and macrophages) in cultured rat splenocytes and RANKL expression in B cells were determined by flow cytometric analyses. B-cell capacity for induction of osteoclast differentiation was evaluated by coculture with RAW 264.7 cells followed by a tartrate-resistant acid phosphatase (TRAP) activity assay. Results:, The expression levels of interleukins 4 and 10 in cultured cells were not changed in the presence of A. actinomycetemcomitans until cultured for 3 days, and peaked after 7 days. After culture for 10 days, the percentages of B and T cells, the overall RANKL messenger RNA transcripts, and the percentage of RANKL-expressing immunoglobulin G-positive cells were significantly increased in the presence of A. actinomycetemcomitans. These increases were considerably greater in cells isolated from A. actinomycetemcomitans -immunized animals than from non-immunized animals. RAW 264.7 cells demonstrated significantly increased TRAP activity when cocultured with B cells from A. actinomycetemcomitans -immunized animals. The addition of human osteoprotegerin-Fc to the culture significantly diminished such increases. Conclusion:, This study suggests that B-lymphocyte involvement in the immune response to A. actinomycetemcomitans through upregulation of RANKL expression potentially contribute to bone resorption in periodontal disease. [source]