lec 4- regulating gene expression Flashcards
what is gene expression?
the flow of info from the gene (DNA) to RNA (transcription) to protein (translation)
what are transcription factors?
regulatory proteins that bind to specific DNA sequences, either activate or inhibit sequences
can signals activate transcription factors in target cells?
yes
what does Wnt signalling do?
-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
how does gene expression control development?
developmental genes code for proteins, they control when and where certain different proteins are made in different cells
what is gene expression profiling?
it is an approach used to identify genes that are expressed in a particular tissue or at a particular stage of development
how is it determined when and where specific genes are expressed?
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
what is antibody labelling?
-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
what are reporter genes?
-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
what is a commonly used reporter protein?
green fluorescent protein
why is using GFP good?
can be visualized in living organisms and has multiple different colors
what is a genotype?
the genetic info that an organism acquires from its parents
what is a phenotype?
the visible appearance, internal structure and biochemistry of the organism
what are the two types of mutations?
-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
what is the forward genetic approach?
They look for a mutated individual in a population, when found, they use genetic mapping techniques to identify the gene causing the mutation
what is the reverse genetic approach?
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
what are the three ways to knock out specific genes in the reverse genetics approach?
- introduce complementary DNA or RNA that hybridizes with the mRNA preventing its use in transcription
- disrupt the specific gene via homologous recombination
- CRISPR tech that allows scientists to precisely edit specific genes
what is redundancy?
when multiple pathways exist to achieve the same outcome, it allows embryos to consistently achieve the correct outcome during development
what are the two common questions biologists ask when studying specific genes?
-when and where is the gene expressed during development?
2. what happens to development when expression of the gene is altered?
