Genome - health and disease

Question 1

What are homebox genes?

Answer 1

Large family of similar genes that direct the formation of many body structures during embryonic development.
Present on every human chromosome.
Produce proteins that are transcription factors (about 60 a.a.’s)

Question 2

Homebox genes were first discovered in what species?

Answer 2

drosophila

Question 3

With what area of the DNA do homebox genes interact?

Answer 3

Major groove of the DNA via number of H-bonds and hydrophobic interctions

Question 4

Describe what happened to drosophila when their homebox genes were mutated?

Answer 4

Legs grow from the head where antenna should be

Question 5

What does MSX stand for?

Answer 5

Muscle Segment Box

Question 6

What is MSX?

Answer 6

A transcription factor that consists of 3 genes: Msx1, Msx2, and Msx3.
Homebox gene family.
These act as transcriptional PREPRESSORS by interacting directly with the TATA binding protein

Question 7

What is TATA and what iccurs when it interacts with MSX

Answer 7

TATA binding protein is a component of the general transcription. MSX sequesters TATA and turns it off, thus INHIBITING its activity and causing TRANSCRIPTION REPRESSION.

Question 8

___ demonstrates greater affinity for DNA while ___ is a more potent repressor

Answer 8

Msx2 demonstrates greater affinity for DNA while Msx1 is a more potent repressor

Question 9

Mutation of what cuses orofacia clefting and tooth agenesis in humans?

Answer 9

Msx1

Question 10

Define oligodontia

Answer 10

condition in which multiple teeth fail to develop. Caused by MSX1 gene mutation

Question 11

What is the PAX family?

Answer 11

• family of 9 genes

- transcription factors for a DNA-binding protein

Question 12

Which PAX family gene products are expressed in developing teeth?

Answer 12

PAX1 and PAX9

Question 13

How do the PAX9 gene products function?

Answer 13

They function by binding the enhancer DNA sequences and modifying transcriptional activity of downstream genes

Question 14

Mutations in PAX 9 gene have been implicated in ___ ___

Answer 14

tooth agenesis

Question 15

Define missense mutation

Answer 15

Switch one amino acid for another.
May or may not affect the protein function, depending on whether the change is “CONSERVATIVE” or ‘NON-CONSERVATIVE” and what the amino acid does

Question 16

Define nonsense mutation

Answer 16

a stop codon is generated (due to adding or replacing a single nucleotide).

Question 17

Insertion mutation

Answer 17

insertion of a single nucleotide

Question 18

Loss of a single nucleotide is known as a ___ mutation

Answer 18

deletion

Question 19

Duplication mutation

Answer 19

A piece of DNA is abnormally copied one or more times. May alter the function of the resulting protein

Question 20

Frameshift mutation

Answer 20

Changes the gene’s reading frame and this changes the code for amino acids. Usually non-functional resulting protein.
Insertion, deletions and duplications can all be considered as frameshift mutation

Question 21

A mutation which does not change an amino acid but can still have a phenotypic effect in some cases is known as ___ mutation

Answer 21

silent

Question 22

How can a silent mutation have a phenotypic effect?

Answer 22

by speeding up or slowing down protein synthesis, or by affecting splicing

Question 23

PAX9 frame shift, deletion and missense termination mutations cause ____ in both the permanent and primary dentition

Answer 23

hypodontia

Question 24

___ ___ mutations of PAX9 genes affect only the permanent dentistion

Answer 24

missense substitution

Question 25

T/F: PAX 9 and MSX1 interact duting tooth deveopment at both the gene and protein level

Answer 25

true

Question 26

What are stem cells?

Answer 26

cells capable of dividing indefinitely and have the ability to produce specialized cells

Question 27

What are the 3 types of stem cells?

Answer 27

- TOTIPOTENT: cells with capacity to specialize into ALL the cells necessary to form a complete embryo, including placental tissue - PLURIPOTENT: cells capable of producing most tissues of the body, but not placental tissues - MULTIPOTENT: give rise to several other cells types (eg. blood stem cells can give rise to various blood cell types, but not brain cells)

Question 28

Dental stem cells include:

Answer 28

dental pulp stem cells, stem cells from human exfoliated deciduous teeth, periodontal ligament stem cells, stem cells from the apical papilla, and dental follicle stem cells

Question 29

Technique which uses genes to treat or prevent disease is known as:

Answer 29

gene therapy

Question 30

In simple terms, describe gene therapy using an adenovirus vector

Answer 30

A new gene is injected into an adenovirus vector and the modified DNA is introduced into a human cell. If this works, the new gene will produce a functional protein

Question 31

What is exon skipping?

Answer 31

A mechanism for restoring the reading frame within a gene

Question 32

The molecule that finds a string of DNA and makes a precision cut is known as:

Answer 32

CRISPR

Question 33

CRISPR consists of a strand of ___ and an enzyme called __

Answer 33

CRISPR consists of a strand of RNA and an enzyme called Cas

Question 34

What is the purpose of CRISPR?

Answer 34

The RNA in CRISR recognizes and docks onto the VIRUS DNA nad Cas makes a cut in the DNA, DISABLING THE VIRUS.

Question 35

What type of engineering is being used to prevent browning in mushrooms?

Answer 35

CRISPR edited white mushrooms

Question 36

How are the effects of growth factor mediated?

Answer 36

through binding to cell surface receptors

Question 37

Growth factors have been shown to be positive for what?

Answer 37

wound healing

Question 38

What does exon skipping do?

Answer 38

Exon skipping is a form of RNA splicing that causes cells to skip over faulty or misaligned sections of genetic code, leading to a truncated but still functional protein despite mutation