What is Transcription?

• Transcription is the process in which genetic information encoded in DNA is copied into a complementary RNA molecule. It is a crucial step in gene expression and occurs in the nucleus of eukaryotic cells.

Eukaryotic Chromosomes

• Eukaryotic chromosomes are long, thread-like structures found in the nucleus of eukaryotic cells. They contain the genetic information in the form of DNA molecules. Eukaryotes, including humans, have multiple linear chromosomes.

RNA Polymerase

• RNA polymerase is an enzyme responsible for catalyzing the transcription process. It binds to a specific region of DNA called the promoter and synthesizes an RNA molecule that is complementary to the DNA template strand.

Promoter of Protein-Coding Region DNA

• The promoter is a specific DNA sequence located upstream (towards the 5’ end) of the protein-coding region of a gene. It serves as a recognition site for RNA polymerase and other transcription factors to initiate transcription.

Transcription Initiation

• Transcription initiation is the first step of transcription. It involves the binding of RNA polymerase to the promoter region of the DNA. Once bound, RNA polymerase begins unwinding the DNA double helix.

Production of Mature mRNA

• The production of mature mRNA involves several steps after transcription:
  1. Capping: A 7-methylguanosine cap is added to the 5’ end of the pre-mRNA.
  2. Polyadenylation: A poly-A tail is added to the 3’ end of the pre-mRNA.
  3. Splicing: Introns (non-coding regions) are removed, and exons (coding regions) are joined together to form the mature mRNA.

Steps of Pre-mRNA Processing

• Pre-mRNA processing includes capping, polyadenylation, and splicing, as mentioned above. These steps are essential for the maturation of the pre-mRNA into a functional mRNA molecule.