Gene Expression Regulation Vocabulary

Flashcards on gene expression regulation, focusing on vocabulary from lecture notes.

Transcription

The process where RNA polymerase decodes DNA to produce a strand of messenger RNA (mRNA). This process occurs in the nucleus in eukaryotes and cytoplasm in prokaryotes. It involves initiation, elongation, and termination stages. Several regulatory elements such as transcription factors and enhancers influence the efficiency and accuracy of transcription.

RNA Polymerase II

The molecule involved in eukaryotic transcription of mRNA.

Transcription Initiation Complex (TIC)

A complex of regulatory molecules that forms before transcription can begin.

Transcription Factors

Proteins that are key regulators of gene expression and bind to specific DNA sequences or motifs.

Promoter

An area of the gene where transcription factors bind, recognizing a specific nucleotide sequence called the TATA box.

Enhancer

A DNA sequence that may be located some distance away from the TIC and moves into position to facilitate transcription.

Mediator

A large complex of proteins that binds to activator proteins on the enhancer, building a bridge between RNA polymerase, transcription factors, and the enhancer sequence.

Transcription Elongation Factors

Proteins that stabilize the connection between RNA polymerase and DNA and determine the speed of transcription.

Methylated Cap

A protective cap added to the 5’ end of the mRNA transcript to prevent attack by cellular enzymes.

Polyadenylation

The attachment of a series of adenines to the 3’ end of the newly terminated transcript, providing stability to mRNA.

Splicing

The process that removes introns from mRNA, with the remaining exons joined together to form a mature mRNA molecule.

Spliceosomes

Complexes of RNA and proteins that carry out splicing.

Introns

Non-coding sections of an RNA transcript, that are removed before translation.

Exons

Coding sections of an RNA transcript, that remain after splicing and are joined together.

Alternative Splicing

A process where different exons are included or excluded in the mature mRNA product, resulting in different isoforms and protein products.

Translation

The process during which an mRNA nucleotide sequence is translated into a protein’s amino acid sequence.

Initiation Factors

Regulatory molecules that form an initiation complex, including proteins, ribosome, mRNA, and tRNA during translation.

Elongation Factors

Proteins that help deliver appropriate tRNA to the ribosome during translation elongation.

Release Factors

Proteins involved in translation termination that recognize stop codons (UAA, UAG, UGA) in the mRNA sequence. Upon binding to the stop codon, release factors cause the hydrolysis of the bond between the tRNA and the peptide chain, leading to the release of the newly synthesized peptide. Additionally, they facilitate the dissociation of the ribosomal subunits from the mRNA, allowing the ribosome to be recycled for further translation events.