RNA Processing and Molecular Blotting Techniques

Vocabulary flashcards covering pre-mRNA processing, alternative splicing mechanisms, gene structure features, and standard molecular blotting methodologies.

Intron

A region of DNA that remains inside the nucleus and must be removed through splicing so that coding sequences can be exported.

Exon

A protein-coding region of a gene that is retained after splicing and exported out of the nucleus to be translated.

Precursor mRNA (pre-mRNA)

The raw, unedited initial RNA transcript synthesized directly from a gene before undergoing capping, splicing, and polyadenylation.

5' Cap

A chemical modification added to the five prime end of eukaryotic mRNA that aids in directionality and protects against degradation by nucleases.

Poly-A Tail

A modification consisting of many adenines added to the three prime end of eukaryotic mRNA to protect against degradation and facilitate nuclear export.

Splicing

The molecular process of cutting out introns and joining exons together in specific combinations to create mature mRNA.

Calcitonin

A hormone produced in the thyroid tissue when exons 1, 2, 3, and 4 are spliced together, functioning to regulate calcium levels.

CGRP

A hormone produced in neurons by skipping exon 4 and joining exons 5 and 6, used as part of signaling pathways to transmit electrical signals through the body.

5' UTR

The untranslated region located on the five prime end of an mRNA between the transcription start site and the start codon.

3' UTR

The untranslated region located downstream of the stop codon up to the polyadenylation sequence on the three prime end of the mRNA.

Shine-Dalgarno Sequence

A consensus sequence found in the 5' UTR of prokaryotic mRNA that the ribosome recognizes and binds to in order to align with the correct start codon.

Kozak Sequence

A eukaryotic consensus sequence akin to the Shine-Dalgarno sequence that helps coordinate ribosome binding and initiation.

Blotting

A laboratory method where molecules separated on a fragile gel are transferred upward via wicking buffer onto a durable nylon membrane or filter for experimental probing.

SNOW DROP

A mnemonic device representing blotting types and their targets: Southern blot for DNA, Northern blot for RNA, and Western blot for Protein.

Southern Blot

A technique named after Edward Southern that visualizes specific DNA sequences from an organism's total DNA using restriction enzymes and complementary probes.

Northern Blot

A molecular method used to visualize and approximate the size and quantity of specific RNA molecules within an entire cell's RNA using labeled probes.

Western Blot

An analytical technique used to detect, visualize, and approximate the size and amount of a specific protein from a cellular extract using antibodies.

Probe

A complementary base-pairing piece of DNA modified with a fluorescent or radioactive label to locate and highlight a specific target nucleotide sequence.

Restriction Enzyme

A molecular scissor protein that scans DNA and cuts both strands at a specific recognition target sequence, independent of coding frames or codons.

EcoR1

A restriction enzyme derived from E. coli that specifically recognizes and cleaves the DNA sequence GAATTC.