Week 7 Flashcards
euchromatin
permissive chromatin environment; need HATs (acetylate histones) and ATP-dependent chromatin remodeling enzymes (slide nucleosomes around, allowing access to specific sequences in the DNA); opening chromatin is necessary but not sufficient for transcription, must have RNA polymerase recruited to the promoter as well
transcription stimulated by activators
- activator proteins bind to enhancers
- activator proteins interact with general transcription factors, mediator proteins, or RNAP2
- so activator proteins recruit RNAP2
modular interactions
allow different transcription factors to recruit the same proteins to different DNA sequences
introns
noncoding regions, must be removed by RNA splicing by the spliceosome from the DNA sequence during RNA processing
alternative splicing
a certain exon being included or not, making two different proteins
amplifying RNA
make a cDNA copy by reverse transcription, then amplify by PCR (RT-PCR)
RT-PCR
- degrade DNA with DNase, prime reverse transcription
- synthesize cDNA
- regrade RNA with RNase
- PCR. first cycle generates double-stranded DNA. second cycle similar to first cycle of a normal PCR reaction
adding DNA to a plasmid
- cut plasmid with restriction enzymes
- cut DNA to be inserted to generate compatible ends
- use DNA ligase to seal up the plasmid, which now contains the insert DNA
affinity tags
purifies proteins, gets protein of interest away from the other molecules
repair by NHEJ
fixes the site, occasionally an inaccurate repair because it does insertions and deletions, causing frameshift mutations and inactivation of the gene
repair by homologous recombination
allows you to replace the sequence with a new sequence, changes sequence of gene