1. Regulation of gene expression

Question 1

What makes up the human genome?

Answer 1

Question 2

What are the 2 types of gene expression?

Answer 2

1. Constitutive - Products made by cells all the time, housekeeping gene, expression is constant
2. Regulated - TIme (developmental), place (cell type), amount, in response to signals. Under tight regulation

Question 3

What are the different types of genes and their products?

Answer 3

Question 4

Which end of the mRNA attaches to the ribosome?

Answer 4

5’ end

Question 5

How does the RNA get spliced?

Answer 5

By using a large complex of ribonucleoprotein called the spliceosome

Question 6

Describe the characteristcis of chromatin domain

Answer 6

Proteins that attach on histone determines closed/open conformation

Distance between chromatin can change, chromatin can reside in different position in the nucleus.

Question 7

What are CpG islands and patterns of DNA methylation across the genome and genes?

Answer 7

GpG islands are associated with 5’ region of genes

Often surrounded by promoters of constitutively expressed genes; also found at promoters of ~40% regulated genes - usually UNMETHYLATED

Question 8

What determines the epigenetics of a gene?

Answer 8

Question 9

What are the determinaints of chromatin function?

Answer 9

Question 10

Where can gene expression be regulated?

Answer 10

• Transcription
• Post-transcriptional processing
• mRNA degradation

Question 11

What is required to initiate transcription?

Answer 11

Minimum requirement

RNA polymerase

Transription factor binding at promoter (TATA box)

Promoters (the major on-off switches in genes

Further regulation

DNA looping

Direct interaction with other cis-acting DNA sequences (enhancers, silencers)

ncRNAs

trans-acting proteins

Question 12

How does one gene produce more than one protein?

Answer 12

Question 13

What is alternative splicing? give an example

Answer 13

Alternatiie splicing is different exons from a strand of ene that lead to different protein products.

An example is alpha troponin and beta troponin

Question 14

Types of alternative splicing?

Answer 14

Question 15

What are the types of non-coding RNAs?

Answer 15

• Long non-coding RNAs (lncRNAs)
• Short interfering RNAs (siRNA)
• Micro RNAs (miRNA)

Question 16

How does long non-coding RNAs elicit its function?

Answer 16

A. Compete with enzymes of transcription to regulate transcription

B. Act as scaffold for different proteins to work on DNA and regulate transcription

C. Guiding other molecules

D. Enhance promoter region

Question 17

How does siRNA work?

Answer 17

Complimentary to mRNA

Form called RISC and degrade mRNA

Has high complimentarity

Can be exploited in gene therapy, to repress mRNA, can artificially produce artificial siRNA to treat beta thalassemia to repress alpha globin

Question 18

What the heck is miRNA?

Answer 18

Short single strand of mRNA complexed with RNA-induced silencing complex that attach and hybridize to supress translation

Low complimentarity