analyzing gene expression

Question 1

microarrays are used to study?

Answer 1

relative RNA amounts between two sample or to compare RNA levels in one sample to a normal reference

Question 2

when using microarrays, the two samples of RNA are labeled with?

Answer 2

fluorescent dye of different colors that are mixed and applied to an array chip
the chip contains binding sites for every known gene, which acts as a probe to determine transcript levels in the samples

Question 3

in situ hybridiztion (ISH) can be used to determine?

Answer 3

expression of a gene of interest in a tissue, or in an embryo

Question 4

what are the steps of ISH?

Answer 4

• a thin slice of tissue is sample onto a microscope slide, the tissue is permeabilized to open the cell membrane
• a labeled probe is added and bind to the transcript being studied
• an enzyme-linked antibody is added and binds to probe
• when a substrate for the enzyme is added, the target transcript-probe-antibody complex is detect

Question 5

immunohistochemistry (IHC) is a technique similar to ISH, but it is specific to?

Answer 5

proteins instead of nucleic acids

Question 6

IHC requires?

Answer 6

an antibody against a known protein so that this antibody can be recognized by a secondary antibody, which is either linked to an enzyme or fluorescent molecule

Question 7

IHC is used in real life for?

Answer 7

breast cancer biopsies comparing estrogen receptor, progesterone receptor, and a plasma membrane receptor called HER2

Question 8

flow cytometry uses the sample prinicples as ISH, IHC, etc but involves?

Answer 8

single cells that are stained for certain protein markers using specific antibodies which are linked to a fluorescent tag

Question 9

in flow cytometrey, light detectors are used to?

Answer 9

emit light from the fluorescent tag to give information on cell size and how many cells in the sample express each of the markers that were labeled