This protocol describes an in vitro transcription assay that allows for a single round of transcription from in vitro assembled chromatin. Comparing the activity of a receptor or transcriptional coactivator in an assay that measures only a single round of transcription with the results from multiple rounds of transcription can help elucidate the mechanism of transcriptional activation by those factors. - [Read Assay:Single Round of In Vitro Transcription from Assembled Chromatin Templates Using a HeLa Cell Ex]
This calcium phosphate transfection method works best in cell lines that are 1) highly transformed and 2) adherent (Hela, U2OS, SAOS2, AdAH, NPC-KT and obtain from 20% to 100% transfection efficiency depending
on the cell line). Works well for transient experiments but precautions should be used in the design and interpretation of experiments based on the discussion below. Also works
very well for generating stable cell lines. This method is quite sensitive to the amount of input plasmid. - [Read Calcium Phosphate Transfection Method]
The following protocol can be used for the development of stable cell lines expressing GFP fusion proteins. Although optimal transfection procedures (e.g., calcium phosphate, electroporation, or FuGENE 6 [Roche Applied Science]) vary depending on cell type, this general transfection procedure has been successful for stable transfection of HeLa, A-431, U2OS, BHK, and HT1080 cells. - [Read Constructing and Expressing GFP Fusion Proteins]
Protocol for high-throughput immunostaining. Includes: [edit] Detection of 14-3-3 in U2OS and HeLa cells by immunofluorescence. - [Read High-Throughput Immunostaining Protocol]
Specific molecular components can be efficiently labeled by a combination of three methods: chemical transfection of GFP-fusion constructs, staining of chromosomes with the DNA-specific, fluorescent dye Hoechst 33342, and microinjection of fluorescently conjugated proteins. This procedure provides an example of using all three methods in sequence to label components of living HeLa cells. These methods should be followed in the order presented, but any of them can be omitted when not needed. - [Read Imaging Hoechst-Labeled Chromosomes and Fluorescent Proteins during the Cell Cycle]
Fluorescence microscopy provides a powerful tool for imaging molecular components in living cells. Specific molecular components can be efficiently labeled by a combination of three methods: chemical transfection of GFP-fusion constructs, staining of chromosomes with the DNA-specific, fluorescent dye Hoechst 33342, and microinjection of fluorescently conjugated proteins. This procedure provides an example of using all three methods in sequence to label components of living HeLa cells. - [Read Imaging Hoechst-Labeled Chromosomes and Fluorescent Proteins during the Cell Cycle]
Procedure is used to prepare DNA simultaneously from many different types of samples or tissues. Although the DNA is generally too small (approx. 80 kb) for efficient construction of genomic DNA libraries, it gives excellent results in Southern hybridizations and PCRs. Cultured aneuploid mammalian cells (2 x 107, e.g., HeLa cells) yield 100 µg of DNA in a volume of 1 ml. - [Read Isolation of DNA from Mammalian Cells by Spooling Protocol]
Method of choice when large amounts of mammalian DNA are required, for example, for Southern blotting (Rapid Isolation of Mammalian DNA, Rapid Isolation of Yeast DNA, Southern Blotting: Capillary Transfer of DNA to Membranes) or for construction of genomic libraries in bacteriophage {lambda} vectors. Approximately 200 µg of mammalian DNA, 100-150 kb in length, is obtained from 5 x 107 cultured aneuploid mammalian cells (e.g., HeLa cells). - [Read Isolation of High-molecular-weight DNA from Mammalian Cells Using Proteinase K and Phenol Protocol]
This protocol describes nuclear and cytoplasmic fractionation of tissue culture cells and a method for Western blot detection of proteins using the Odyssey Infrared Imaging System. This protocol was used to detect expression of the "small" Tap protein in 293T, HeLa and COS cells. The Odyssey system has several advantages over the more widely used chemiluminescent detection methods. - [Read Western Blot Analysis of Sub-Cellular Fractionated Samples Using the Odyssey Infrared Imaging System]