14 - Gene Expression Technologies

Question 1

Gene expression

Answer 1

Process where heritable information in a gene (the sequence of DNA Base pairs) is made into a functional gene product (e.g. protein or RNA). Plays a central role in controlling cell phenotype.

Question 2

When is Eukaryotic gene expression regulated

Answer 2

• In nucleus: during transcription and RNA processing
• Cytoplasm: during translation
• Further regulation through post translational modification of proteins

Question 3

Advantages of regulation of gene expression

Answer 3

Conserves energy (heaps of energy would be needed to express all genes at all times), and space (DNA must be unwound from tightly coiled structure)

Question 4

Central dogma of molecular biology

Answer 4

DNA –(Transcription)–> RNA –(Translation)–> Protein

Question 5

Housekeeping genes

Answer 5

Expressed in most cells at high levels and are required to maintain cell function

Question 6

Examples of housekeeping genes

Answer 6

BETA-ACTIN (structural protein) and GAPDH (involved in glycolysis)

Question 7

Cell specific/inducible genes

Answer 7

Show a restricted pattern of expression which may depend on cell type, stage of development or exposure to external stimuli

Question 8

Examples of cell specific/inducible genes

Answer 8

BETA-GLOBIN (HBB), Insulin (INS), Myosin (MYH2)

Question 9

Examples of responses to external stimuli

Answer 9

• Stress
• Temperature
• Nutrition
• Immune activation
• Circadian rhythm

Question 10

Types of gene expression technologies

Answer 10

• RNA profilling technologies: quantify RNA molecules
• Gene expression reporter systems

Question 11

Examples of RNA profiling technologies in order of smallest to largest amount of genes assayed

Answer 11

• RT-qPCR
• Single cell RNA-seq and Spatial transcriptomics
• Microarray
• RNA-seq and CAGE-seq

Question 12

RT-qPCR

Answer 12

Reverse Transcription Quantitative Polymerase Chain Reaction. Method used to measure the expression of a small number of known genes

Question 13

RT-qPCR

Answer 13

Reverse Transcription Quantitative Polymerase Chain Reaction. Method used to measure the expression of a small number of known genes. Involves the synthesis of cDNA from mRNA prior to PCR

Question 14

Requirements of RT-qPCR

Answer 14

• Addition of fluorescent probe that binds to DNA
• Measurement of fluorescence signal after each PCR cycle

Question 15

SYBR green

Answer 15

Fluorescent probe used to quantify dsDNA. When bound to dsDNA, absorbs blue light and emits green

Question 16

Gene expression microarray

Answer 16

Microscope slides used to measure the expression of thousands of know genes

Question 17

RNA-seq and CAGE-seq

Answer 17

Methods that are used to measure the expression of thousands of unknown and known genes.

Question 18

what does CAGE-seq stand for

Answer 18

Capped Analysis of Gene Expression

Question 19

Differences between RNA-seq and CAGE-seq

Answer 19

• RNA-seq sequences broad regions of expressed genes
• CAGE-seq sequences narrow sites of activity with greater depth