Transcription and mRNA Processing

These flashcards summarize key concepts and processes related to transcription and mRNA processing as covered in the lecture notes.

What allows transcription to be regulated in eukaryotic cells?

Transcription can be regulated in response to internal and external cues, leading to tissue-specific and temporal-specific gene expression.

What are cis regulatory elements?

Cis regulatory elements, like enhancers, are nucleotide sequences that contribute to transcriptional regulation in eukaryotic cells.

What distinguishes trans-acting factors from cis-acting elements?

Trans-acting factors are proteins that bind to cis-acting sequences, such as enhancers and silencers.

What is the role of RNA polymerase II in transcription initiation?

RNA polymerase II carries out the synthesis of RNA from the DNA template.

What happens during the capping of mRNA?

A 5’ cap is added to the mRNA to protect it from exonucleases and assist in translation.

How are introns removed from pre-mRNA?

Introns are removed through a process called splicing, facilitated by the spliceosome.

What is alternative splicing?

Alternative splicing is the process by which a single gene can lead to multiple mRNA variants and therefore different protein products.

What is the significance of the AAUAAA sequence in eukaryotic mRNA?

The AAUAAA hexanucleotide is a consensus sequence that signals for cleavage and polyadenylation at the 3’ end of mRNA.

What enzyme adds acetyl groups to histones during transcription initiation?

Histone Acetyl Transferase (HAT) adds acetyl groups to histones.

What is the function of TFIIH in transcription?

TFIIH phosphorylates RNA polymerase II, which is critical for the initiation of transcription.

What does the term 'splicing' refer to?

Splicing refers to the process of removing introns from pre-mRNA and connecting exons to form a mature mRNA.

What are the components of the spliceosome?

The spliceosome is made up of several snRNPs, each composed of uracil-rich snRNAs and proteins.

What occurs at the 3' end of mRNA processing in eukaryotes?

The 3' end undergoes cleavage and polyadenylation, adding a poly-A tail.

What is the impact of differential gene expression in eukaryotes?

Differential gene expression allows organisms to have a complex proteome, with various proteins being produced from the same DNA template.

Where does transcription occur in eukaryotic cells?

Transcription occurs in the nucleus of eukaryotic cells.

What is the output of transcription in prokaryotes versus eukaryotes?

In prokaryotes, mRNA is produced directly from DNA, whereas in eukaryotes, pre-mRNA undergoes processing before becoming mature mRNA.