Eukaryotic Transcription and mRNA Processing

These flashcards cover the key vocabulary related to eukaryotic transcription and mRNA processing, including important enzymes, processes, and components involved.

Histone Acetyltransferases (HATs)

Enzymes that add acetyl groups to histones, leading to the loosening of chromatin in eukaryotic transcription.

TATA Box

A promoter sequence located approximately 25 bp upstream of the transcription start site, crucial for initiating transcription in eukaryotic organisms.

RNA Polymerase II

An enzyme responsible for synthesizing mRNA from a DNA template in eukaryotic cells.

5′ Cap

A modified guanine nucleotide, specifically 7-methylguanosine, added to the 5' end of pre-mRNA via a unique 5'-5' triphosphate linkage. This co-transcriptional modification is essential for protecting the mRNA from exonuclease degradation, thereby enhancing its stability. Furthermore, it plays a crucial role in translation initiation by serving as a recognition signal for eukaryotic initiation factors (e.g., eIF4E), which facilitates ribosome binding and efficient protein synthesis.

Polyadenylation

The addition of a poly(A) tail to the 3' end of mRNA which enhances stability and aids in nuclear export.

Spliceosome

A large RNA-protein complex that removes introns from pre-mRNA and joins exons together.

CTD (C-terminal domain)

A domain of RNA Polymerase II that is phosphorylated and coordinates the processing of pre-mRNA.

Intron

Noncoding segments within a gene that are removed during RNA splicing.

Exon

Coding segments that are retained in mRNA after splicing.

Alternative splicing

The process by which different combinations of exons are joined together to produce multiple protein variants from a single gene.