mouse and human genetics

Question 1

2 reasons for using genetic models

Answer 1

1. research into gene function - study effects of insertion/deletion. study effects of over expression of wild type/mutated protein
2. disease model - insertion of human genes into animals. pre-clinical tests of drugs

Question 2

function of mdm2

Answer 2

to maintain p53 at low levels

Question 3

function of mdmx

Answer 3

inhibits p53 transcriptional activity

Question 4

advantages of inbred strains

Answer 4

animals are almost genetically identical therefore more consistent results and no complication from secondary mutations

Question 5

disadvantages of inbred strains

Answer 5

diff results might be obtained in diff backcross strains. results might not occur in an outbred population

Question 6

two types of models and their definition

Answer 6

transgenic - has a foreign gene of dna inserted into its genome
gene targeted - animal which has an alteration in a endogenous gene

Question 7

in transgenic models, how can you control when the gene is expressed?

Answer 7

as the gene is inserted with a specific promoter

Question 8

in transgenic models, what can be used to visualise if the protein is being expressed?

Answer 8

tags such as GFP

Question 9

what is included in a transgene

Answer 9

a promoter/enhancer on the far left (tissue specific), an open reading frame of gene of interest in the middle and a polyA sequence at the end

Question 10

what are IRES sequences

Answer 10

a promoter/enhancer that can be used to express 2 genes

Question 11

how can you insert a transgene

Answer 11

pronuclear microinjection (injection of dna vector into pronucleus). retrovirus mediated gene transfer (rna virus used to transfer genetic material into host cell), oocytes cultured and transferred to recipient female

Question 12

what are some problems associated with transgenes?

Answer 12

positional effect (silencing of transgene expression). multiple site insertion/copy number

Question 13

how can problems with transgenes be overcome?

Answer 13

using recombinases to control the locus to in which the transgene is inserted

Question 14

advantages of gene targeted model

Answer 14

no over expression of exogenous proteins and different modifications possible

Question 15

disadvantages of gene targeted models

Answer 15

slower and more complex than transgenic. more restricted to mice.

Question 16

how is a vector introduced into ES cells

Answer 16

by electroporation

Question 17

what do g418 cells do

Answer 17

kills cells that have not incorporated neomycin selection cassette

Question 18

what do gancyclovir cells do

Answer 18

kill cells that have incorperated the thymidine kinase gene