The RNA Transcript for the Following DNA Template: 3’ - TACGGA - 5'

• The RNA transcript for the given DNA template would be: 5’ - AUGCCU - 3’. This is because in RNA, uracil (U) replaces thymine (T) when pairing with adenine (A), cytosine (C) pairs with guanine (G), and the directionality is from 5’ to 3'.

The Role of Sigma Factor in Transcription

• Sigma factor is a protein in prokaryotes that plays a crucial role in transcription initiation. It helps RNA polymerase recognize the promoter region of DNA and initiate transcription at the correct site. Sigma factor acts as a transcription initiation factor by guiding RNA polymerase to the promoter.

Transcription of Protein-Coding Gene

• Transcription of a protein-coding gene is the process of copying the genetic information from the DNA of the gene into an mRNA molecule. This mRNA serves as a template for protein synthesis during translation.

Promoter of Protein-Coding Region DNA

• The promoter of a protein-coding region DNA is a specific DNA sequence located upstream (towards the 5’ end) of the gene. It contains essential regulatory elements and serves as the binding site for RNA polymerase and transcription factors. The promoter region is crucial for initiating transcription.

Promoter Proximal Element

• The promoter proximal element is a regulatory DNA sequence located close to the promoter region of a gene. It contains binding sites for transcription factors that can influence the rate of transcription initiation. The presence and binding of transcription factors to the promoter proximal element can enhance or repress gene expression.

Structure of Mature mRNA

• Mature mRNA has a specific structure:
  • 5’ Cap: A 7-methylguanosine cap is added to the 5’ end of the mRNA. This cap is essential for mRNA stability and translation initiation.
  • Coding Region (Exons): The coding region of the mRNA contains exons, which are the sequences that code for proteins.
  • 3’ Poly-A Tail: A polyadenine (poly-A) tail is added to the 3’ end of the mRNA. This tail is important for mRNA stability and export from the nucleus.

Production of Mature mRNA

• The production of mature mRNA involves several steps:
  1. Transcription: RNA polymerase synthesizes a complementary RNA strand from the DNA template.
  2. Capping: A 7-methylguanosine cap is added to the 5’ end of the pre-mRNA.
  3. Polyadenylation: A poly-A tail is added to the 3’ end of the pre-mRNA.
  4. Splicing: Introns (non-coding regions) are removed, and exons (coding regions) are joined together to form the mature mRNA.

5’ Modification (Capping)

• The 5’ modification, also known as capping, involves adding a 7-methylguanosine cap to the 5’ end of the pre-mRNA. This cap serves several functions:
  • Protects the mRNA from degradation by exonucleases.
  • Facilitates mRNA export from the nucleus.
  • Aids in translation initiation by interacting with translation factors.

Processing of Pre-mRNA to Mature mRNA

• Processing of pre-mRNA to mature mRNA includes the following steps:
  1. Capping: Addition of a 7-methylguanosine cap to the 5’ end.
  2. Polyadenylation: Addition of a poly-A tail to the 3’ end.
  3. Splicing: Removal of introns (non-coding regions) and joining of exons (coding regions).
  4. Transport: Export of mature mRNA from the nucleus to the cytoplasm for translation.

Steps of Pre-mRNA Processing

• The steps of pre-mRNA processing include:
  1. Transcription: RNA polymerase synthesizes the pre-mRNA.
  2. Capping: Addition of a 7-methylguanosine cap to the 5’ end.
  3. Polyadenylation: Addition of a poly-A tail to the 3’ end.
  4. Splicing: Removal of introns and joining of exons.
  5. Transport: Export of mature mRNA to the cytoplasm for translation.