In: Biology
In a detailed paragraph, starting with normal and cancer intact cells as well as the preparation of the DNA microarray chip, explain in detail how the typical DNA microarray experiment will be performed in order to identify differentially expressed genes. What are the types of probes that can be used for this experiment, and how are they different? Explain how the data will be interpreted.
DNA microarray is performed to detect thousands of gene expression of a cell in same time. To perform a DNA microarray of a cancer cell and normal cell following steps will be performed-
a) mRNA isolation-mRNA will be extracted from normal and cancer cell. Here normal cell be control and cancer cell will be experimental.
b)mRNA reverse transcription and labelling- mRNA from this cells will be reverse transcribed to produce cDNA . After this, each type of cDNA will nedd to label with fluroscent dye. For two different cell types , we need two different fluroscent dye.
c) Hybridization- In this step labelled cDNA from both normal and cancer cell will be added to the microarray chip. The microarry chip will contain thousands of DNA sequences which are known as probes. The type of probe which will be uesd here is DNA sequenceies of different genes which are found in human. Once the cDNAse are added to microarray chip, they will bind or hybridize with the matching DNA sequences present in the chip.
d) Scanning of microaary- when cDNA segments of both normal and cancer will hybridize with the complementary sequences of DNA, the fluroscent label will also give signal accordingly. As there is two different dye present, the fluroscent signal will be expressed in two colours.It is expected that the expression of normal and control cell will be different, pointing that the genes will be expressed differentially in both condition.
To know about the differentially expressed genes between control and cancer cell, the signals obtained in microarray chip will be quantified and normalized. Next, known public database will be mined to identify the DNA sequences and to identify the expressed genes in both sample.