Most biological specimens are relatively transparent, so details of internal and intracellular morphology are difficult to image in untreated living specimens using simple bright-field techniques. Fluorescence microscopy offers greater advantages and possibilities for increasing contrast and determining the specific localization of molecules in cells. Article outlines the three methods most commonly used to introduce an appropriate label into Drosophila tissue without perturbing the process. - [Read Fluorescent Reagents for Live Cell Imaging and Their Introduction into Cells]
This protocol is concerned with the use of iodixanol gradients in an analytical mode to study the membrane localization of a particular protein or function. Continuous gradients are best suited to this task. One of the protocols described in this protocol starts with a discontinuous gradient, but since the gradient is centrifuged at 174,000g for 16 h it will become continuous by diffusion. - [Read Fractionation of Yeast Membranes in Pre-Formed Continuous Iodixanol Gradients]
Protocols for gene expression and protein localization in Arabidopsis. Includes: Detection of the native protein; Detection of a recombinant version; Immunofluorescence detection in Arabidopsis protoplasts; Isolation of Arabidopsis seedling protoplasts; Subcellular localization of GUS-fusion proteins in Arabidopsis seedlings; Localization of Arabidopsis proteins with GUS in situ enzyme assay. - [Read Gene Expression and Protein Localization in Arabidopsis Protocols]
Describes two methods for using the immunoperoxidase reaction to localize antigens at the electron microscope level; one for adherent cultured cells and one for tissue sections. The reaction conditions are first optimized at the light microscope level and then adapted for EM level observation. These methods allow for reliable detection of antigens at the cell surface, within the cell, and especially in membrane bounded organelles. - [Read Immunoperoxidase Methods for Localization of Antigens in Cultured Cells and Tissues]
Direct labeling of purified antibodies is the method of choice when simultaneously visualizing two or more antibodies of the same species, class, or subclass. This allows the localization of multiple antigens to be compared in the same cell, tissue, or sample. Labeled primary antibodies are also useful for improving background-to-readout ratios, and they can be essential for immunoassays in which good quantification is needed. - [Read Labeling Antibodies with Fluorochromes Protocol]
Protocol describes the acquisition and processing of confocal
fluorescent and bright field images of live cells, expressing cyan fluorescent protein(CFP) and/or yellow fluorescent protein (YFP), with a spinning disk confocal head on a Zeiss Axiovert 200 M microscope. This procedure is used to help determine if N- or Cterminal tagging of signaling molecules alters the steady state localization pattern of the signaling protein in question. - [Read Live Cell Spinning Disk Confocal Fluore Imaging of Cells- Colocalization of Fluorescent Protein Tags]
GUS is used as a tag to address nuclear localization whereas GFP is more versatile. GFP is detectable directly in living cells, GUS is only detected indirectly by staining of fixed tissue which may lead to artifacts or may obscure problems with protein solubility. In this protocol, protein localization is routinely assayed after particle-mediated transient transformation of onion epidermal cells. With this method it can be determined rapidly whether a given fusion protein is active and.... - [Read Subcellular Localization of GUS- and GFP-Tagged Proteins in Onion Epidermal Cells]
Small ubiquitin-like modifier (SUMO) is a small molecule, but has a variety of regulatory functions in cells. SUMO modification is involved in transcriptional regulation, subcellular localization, and protein-protein interactions. SUMO conjugation requires sequential E1-dependent activation, E2-dependent conjugation, and E3-dependent ligation steps. Protocol includes: In vivo and in vitro SUMOylation assay and deSUMOylation assay. - [Read Sumoylation and Desumoylation Assays for a Chromatin-Remodelling Complex In Vivo and In Vitro]
Background and methods to study plant transport. Includes new methods to study protein trafficking in plant cells, includes: Identification of protein sorting pathways in non purified samples; Localization of organelle proteins by isotype tagging/isotype-coded affinity tag; Coupling of chemical genomics and proteomics; Top down mass spectrometry; Compartment-specific markers to aid in the purification of organelles. - [Read Understanding Protein Trafficking in Plant Cells Through Proteomics]