A synthetic gene for the human motilin receptor containing 33 unique restriction sites was designed and stably coexpressed in HEK293 cells with the bioluminescent Ca(2+) indicator protein aequorin. The dose-dependent response of the receptor to motilin was demonstrated using transient transfections, and a stable cell line was selected. [(125)I]Motilin binding was used to estimate receptor expression level for the stable cell line, and titration of a membrane preparation indicated a K(d) value of 0.8 nM. The same cell line was used to evaluate a panel of erythromycin-derived agonists and provided EC(50) values for receptor activation that agree closely with data obtained in contractility assays. The peptide antagonist ANQ11125 (Phe3Leu13 motilin 1-14) inhibited motilin induced response with a K(i) value of 10 nM. The system is well-suited for the screening of compound libraries and receptor mutagenesis studies.
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http://dx.doi.org/10.1006/abio.2001.5466 | DOI Listing |
Methods Mol Biol
December 2024
Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich GmbH, Jülich, Germany.
Photocaged compounds are chemical conjugates that are designed to release an active molecule upon exposure to light of a specific wavelength. In recent years, photocaged inducer molecules such as caged isopropyl β-D-1-thiogalactopyranoside (cIPTG) have been increasingly used as a powerful tool for light-driven gene expression in bacteria, allowing researchers to precisely and noninvasively tune the expression of specific target genes. In this chapter, we present a guideline for the synthesis of 6-nitropiperonyl photocaged IPTG (NP-cIPTG) as well as its in vivo application as an optochemical on-switch of gene transcription in Escherichia coli and other bacteria.
View Article and Find Full Text PDFMethods Mol Biol
December 2024
Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.
Optogenetic systems utilize genetically encoded light-sensitive proteins to control cellular processes such as gene expression and protein localization. Like most synthetic systems, generation of an optogenetic system with desirable properties requires multiple design-test-build cycles. A yeast optogenetic toolkit (yOTK) allows rapid assembly of optogenetic constructs using Modular Cloning, or MoClo.
View Article and Find Full Text PDFMethods Mol Biol
December 2024
Systems, Synthetic, and Physical Biology Program, Rice University, Houston, TX, USA.
Optogenetics enables precise control of gene expression in a variety of organisms. We recently developed the first system for optogenetic control of transcription in Bacillus subtilis. This system is based on CcaSR, a light-responsive two-component regulatory system originally derived from Synechocystis PCC 6803.
View Article and Find Full Text PDFJ Cancer Res Clin Oncol
December 2024
Department of Breast Surgery, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde Foshan), #1, Jiazi Road, Lunjiao, Shunde District, Foshan, 528308, Guangdong Province, China.
Objective: To investigate the mechanism by which heterogeneity in breast cancer developed and acted in single-cell transcriptomes.
Methods: The composition of breast cancer based on the single-cell transcriptomes of 54,055 high-quality cells from clinical specimens of 4 malignant and 4 non-malignant patients were investigated.
Results: We identified six common expression programs and six subtype-specific expression programs form malignant epithelial cells.
PLoS Comput Biol
December 2024
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States of America.
For the vast majority of genes in sequenced genomes, there is limited understanding of how they are regulated. Without such knowledge, it is not possible to perform a quantitative theory-experiment dialogue on how such genes give rise to physiological and evolutionary adaptation. One category of high-throughput experiments used to understand the sequence-phenotype relationship of the transcriptome is massively parallel reporter assays (MPRAs).
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