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Institution

Applied Biosystems

About: Applied Biosystems is a based out in . It is known for research contribution in the topics: Mass spectrometry & Capillary electrophoresis. The organization has 1521 authors who have published 1579 publications receiving 285423 citations.


Papers
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Journal ArticleDOI
TL;DR: Findings indicate that SRPK1 may have a role not only in pre-mRNA splicing, but also in the condensation of sperm chromatin, as well as a cytoplasmic pool of SR proteins present in the testis.
Abstract: Arginine/serine protein kinases constitute a novel class of enzymes that can modify arginine/serine (RS) dipeptide motifs. SR splicing factors that are essential for pre-mRNA splicing are among the best characterized proteins that contain RS domains. TwoSRprotein-specifickinases, SRPK1 and SRPK2, have been considered as highly specific for the phosphorylation of these proteins, thereby contributing to splicing regulation. However, despite the fact that SR proteins are more or less conserved among metazoa and have a rather ubiquitous tissue distribution we now demonstrate that SRPK1 is predominantly expressed in testis. In situ expression analysis on transverse sections of adult mouse testis shows that SRPK1 mRNA is abundant in all germinal cells but not in mature spermatozoa. RS kinase activity was found primarily in the cytosol and only minimal activity was detected in the nucleus. In a search for testis-specific substrates of SRPK1 we found that the enzyme phosphorylates human protamine 1 as well as a cytoplasmic pool of SR proteins present in the testis. Protamine 1 belongs to a family of small basic arginine-rich proteins that replace histones during the development of mature spermatozoa. The result of this progressive replacement is the formation of a highly compact chromatin structure devoid of any transcriptional activity. These findings indicate that SRPK1 may have a role not only in pre-mRNA splicing, but also in the condensation of sperm chromatin.

94 citations

Journal ArticleDOI
TL;DR: It is shown that the 1,6-anhydro-N-acetylmuramic acid (anhMurNAc) is returned to the biosynthetic pathway by conversion to N- acetylglucosamine-phosphate (GlcNAc-P), and the kinase gene has been identified by a reverse genetics method.
Abstract: Escherichia coli breaks down over 60% of the murein of its side wall and reuses the component amino acids to synthesize about 25% of the cell wall for the next generation. The amino sugars of the murein are also efficiently recycled. Here we show that the 1,6-anhydro-N-acetylmuramic acid (anhMurNAc) is returned to the biosynthetic pathway by conversion to N-acetylglucosamine-phosphate (GlcNAc-P). The sugar is first phosphorylated by anhydro-N-acetylmuramic acid kinase (AnmK), yielding MurNAc-P, and this is followed by action of an etherase which cleaves the bond between d-lactic acid and the N-acetylglucosamine moiety of MurNAc-P, yielding GlcNAc-P. The kinase gene has been identified by a reverse genetics method. The enzyme was overexpressed, purified, and characterized. The cell extract of an anmK deletion mutant totally lacked activity on anhMurNAc. Surprisingly, in the anmK mutant, anhMurNAc did not accumulate in the cytoplasm but instead was found in the medium, indicating that there was rapid efflux of free anhMurNAc.

94 citations

Journal ArticleDOI
TL;DR: Results are shown for separation and analysis of mixtures of synthetic peptides and also for protease digests of recombinant human growth hormone and horse heart cytochrome c.

93 citations

Journal ArticleDOI
TL;DR: Molecular network mapping of miRNA targets revealed the regulation of activation-induced immune signaling and link top functional networks directly to T lymphocyte immunity, underlining the value of mapping global gene, protein, and miRNA expression.
Abstract: MicroRNAs (miRNAs) regulate specific immune mechanisms, but their genome-wide regulation of T lymphocyte activation is largely unknown. We performed a multidimensional functional genomics analysis to integrate genome-wide differential mRNA, miRNA, and protein expression as a function of human T lymphocyte activation and time. We surveyed expression of 420 human miRNAs in parallel with genome-wide mRNA expression. We identified a unique signature of 71 differentially expressed miRNAs, 57 of which were previously not known as regulators of immune activation. The majority of miRNAs are upregulated, mRNA expression of these target genes is downregulated, and this is a function of binding multiple miRNAs (combinatorial targeting). Our data reveal that consideration of this complex signature, rather than single miRNAs, is necessary to construct a full picture of miRNA-mediated regulation. Molecular network mapping of miRNA targets revealed the regulation of activation-induced immune signaling. In contrast, pathways populated by genes that are not miRNA targets are enriched for metabolism and biosynthesis. Finally, we specifically validated miR-155 (known) and miR-221 (novel in T lymphocytes) using locked nucleic acid inhibitors. Inhibition of these two highly upregulated miRNAs in CD4(+) T cells was shown to increase proliferation by removing suppression of four target genes linked to proliferation and survival. Thus, multiple lines of evidence link top functional networks directly to T lymphocyte immunity, underlining the value of mapping global gene, protein, and miRNA expression.

93 citations

Journal ArticleDOI
TL;DR: The isolation and cloning of a gRNA-interacting polypeptide from Trypanosoma brucei named gBP21 is described, which is arginine-rich and binds to gRNA molecules with a dissociation constant in the nanomolar range, and the gRNA/gBP21 ribonucleoprotein complex is more stable than naked guide RNAs.

93 citations


Authors

Showing all 1521 results

NameH-indexPapersCitations
Richard A. Gibbs172889249708
Friedrich C. Luft113109547619
Alexander N. Glazer7120821068
Vineet Bafna6823642574
Kevin R. Coombes6330823592
Darryl J. Pappin6117029409
Mark D. Johnson6028916103
György Marko-Varga5640912600
Paul Thomas5612844810
Gerald Zon5525611126
Michael W. Hunkapiller5113029756
Bjarni V. Halldorsson5114513180
David H. Hawke501579824
Ellson Y. Chen507128836
Sridhar Hannenhalli4916221959
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20182
20171
20164
20152
20147
201313