Transcriptomics and Proteomics Overview

Transcriptomics

• Definition: The transcriptome is defined as all messenger RNAs (mRNAs) present in a cell, tissue, or organism at a specific time.

• Quantification Techniques:
    - Microarrays:
      - Microarrays are tools used for quantifying the transcriptome.
      - They contain antisense spots for thousands of genes, allowing simultaneous analysis.
      - Bound complementary DNA (cDNA) can be visualized using fluorescent labels that are added to the DNA sequences during the experiment.

  - RNA Sequencing (RNA-seq):
    - RNA-seq is a modern technique that allows for direct sequencing of all mRNAs in the transcriptome at once.
    - It is classified as next-generation sequencing (NGS) technology.
    - The output data from RNA-seq can be interpreted using computational tools to gain insight into gene expression levels.

Proteomics

• Definition: The proteome is defined as all polypeptides (proteins) present in a cell, tissue, or organism.

• Protein Separation and Visualization Techniques:
    - 2-D Gel Electrophoresis:
      - This technique is employed to separate and visualize hundreds of distinct polypeptides simultaneously.
      - It separates proteins based on two properties: isoelectric point and molecular weight.

  - Mass Spectrometry:
    - Mass spectrometry is utilized to identify proteins extracted from specific spots on a 2-D gel.
    - This identification is achieved by comparing their fragment mass profiles to a reference database of known proteins.

• Interactome Analysis:
    - Affinity Capture:
      - This method is used to define the interactome, which describes how proteins bind to each other within the cellular context.

• Protein Microarrays:
    - Another advanced technique allows visualization of thousands of proteins at once.
    - It involves placing specific antibodies in different spots on a microarray to capture and identify targeted proteins in a sample, enhancing the understanding of protein interactions and abundance.