Title: http://www.biomed.miami.edu/arrays/images/agilent_array.jpg
1Example of a DNA Array(note green, yellow red
colorsalso note that only part of the
totalarray is depicted)
http//www.biomed.miami.edu/arrays/images/agilent_
array.jpg
2Methods
Step 1 Create a DNA array (gene chip) by
placing single-stranded DNA for each gene to be
assayed into a separate well on the chip.
3DNA Array Single-stranded copy DNA foreach gene
in a different well.
4Methods
Step 2 Extract mRNA from biological tissues
subjected to an experimental treatment and from
the same tissue subjected to a control treatment.
Step 3 Make single-stranded DNA from the mRNA
using color coded nucleotides.
5Extract mRNA from Control Cells
Extract mRNA from Experimental Cells
Make single-stranded cDNA using green nucleotides
Make single-stranded cDNA using red nucleotides
cDNA complementary DNA (DNA synthesized from
RNA)
6Methods
Step 4 After making many DNA copies of the RNA,
extract an equal amount of cDNA from the controls
experimentals and place it into a separate
container.
7(No Transcript)
8Methods
Step 5 Extract a smallamount in a pipette.
9Methods
Step 6 Insert into first well.
10Methods
insert intosecond well, etc.
Step 7 Extractmore cDNA and
11Methods
Step 8ff Continue until all wells arefilled.
12Methods
Step 9 Allow to hybridize, then wash away all
single-stranded DNA.
13Result
- Some wells have no color-coded cDNA (no mRNA in
either type of cell) - Some wells have only red (i.e., expressed only in
experimental cells) - Some wells have only green (i.e., expressed only
in control cells) - Some wells have both red and green in various
mixtures (expressedin both experimental and
control cells)
14Methods
Step 10 Scan with a laser set to detect the
color process results on computer.
15Results
The colors denote the degree of expression in the
experimental versus the control cells.
Gene not expressed in control or in experimental
cells