lec 4- regulating gene expression

Question 1

what is gene expression?

Answer 1

the flow of info from the gene (DNA) to RNA (transcription) to protein (translation)

Question 2

what are transcription factors?

Answer 2

regulatory proteins that bind to specific DNA sequences, either activate or inhibit sequences

Question 3

can signals activate transcription factors in target cells?

Answer 3

yes

Question 4

what does Wnt signalling do?

Answer 4

-it binds to a receptor which lets the destruction complex to bind to the receptor rather than the b-catenin (transcription factors)
-this allows b-catenin to active the transcription of target genes because it wasn’t degraded

Question 5

how does gene expression control development?

Answer 5

developmental genes code for proteins, they control when and where certain different proteins are made in different cells

Question 6

what is gene expression profiling?

Answer 6

it is an approach used to identify genes that are expressed in a particular tissue or at a particular stage of development

Question 7

how is it determined when and where specific genes are expressed?

Answer 7

cells contain mixtures of single stranded mRNA molecules, if we want to test for gene A, labelled DNA probes that bind to gene A mRNA are made, then they are added and if they bind to the gene A mRNA molecules, we know that they exist at that time

Question 8

what is antibody labelling?

Answer 8

-the detection agent is an antibody that recognizes the protein of interest
-the embryo is fixed in a preservative and the primary antibody recognizes the fixed tissue
-the labelled secondary antibody binds to the primary antibody

Question 9

what are reporter genes?

Answer 9

-artificially constructed DNA sequences consisting of the gene of interest fused to an easily detectable protein are constructed
-needs a promoter region to switch on expression of the protein at the correct time and place during development

Question 10

what is a commonly used reporter protein?

Answer 10

green fluorescent protein

Question 11

why is using GFP good?

Answer 11

can be visualized in living organisms and has multiple different colors

Question 12

what is a genotype?

Answer 12

the genetic info that an organism acquires from its parents

Question 13

what is a phenotype?

Answer 13

the visible appearance, internal structure and biochemistry of the organism

Question 14

what are the two types of mutations?

Answer 14

-recessive mutations that can be seen in carrier
-semidominant mutations where the dominant allele is causing the mutation but if it has one wildtype allele, it is less severe

Question 15

what is the forward genetic approach?

Answer 15

They look for a mutated individual in a population, when found, they use genetic mapping techniques to identify the gene causing the mutation

Question 16

what is the reverse genetic approach?

Answer 16

they start off with a sequence of a gene and then they remove or block the genes functions to see which mutations it causes and its effects on development

Question 17

what are the three ways to knock out specific genes in the reverse genetics approach?

Answer 17

1. introduce complementary DNA or RNA that hybridizes with the mRNA preventing its use in transcription
2. disrupt the specific gene via homologous recombination
3. CRISPR tech that allows scientists to precisely edit specific genes

Question 18

what is redundancy?

Answer 18

when multiple pathways exist to achieve the same outcome, it allows embryos to consistently achieve the correct outcome during development

Question 19

what are the two common questions biologists ask when studying specific genes?

Answer 19

-when and where is the gene expressed during development?
2. what happens to development when expression of the gene is altered?