The Central Dogma Flashcards
What is true of cells and their expression of genes?
Often, cells are always expressing genes, but at different amounts and rates, due to a difference in the ability of specific transcription factors.
What are 5 general places to regulate gene expression?
Chromatin remodeling, transcription factor regulation, mRNA splicing/maturation, destruction of mRNAs, or protein level phosphorylation
Nucleosome
Histone octamer surrounded by DNA
Inactive genes [methyl/acetyl]
Methylated DNA in promoter, and methylated, deacetylated histones
Active genes
acetylated, non-methylated histones
What do acetyl groups do to histones?
It spreads them apart, unwinding the DNA
Promoter
sequence that starts the sequence of an active gene
What are CpG islands?
They are places where a transcription factor binds and activates a promoter to transcribe the active gene
Where is DNA methylation high?
In primordial germ cells, right before fertilization, and at the embryo stage.
General transcription factors
bind to gene promoters and organize the transcriptional machinery
Regulatory transcription factors
bind to enhancers to make transcription more or less efficient
Where is the TATA box located?
In the promoter sequence.
What must be true before RNA polymerase can bind to the gene?
Several General transcription factors must be present
How to regulatory transcription factors interact with enhancers?
They can create a 3d complex such as the mediator complex which more easily allow RNA polymerase to bind.
Where in relation are enhancers located to the active gene?
Usually far away
What are two properties of regulatory transcription factor binding that promotes differentiation and variation?
Combinations of transcription factors, and cascades can induce variability
How do transcription factors ensure differential gene expression?
Specific tissues have specific transcription factors that activate tissue specific enhancer sequences
MyoD1 [explanation, sufficiency/necessity]
Can induce differentiation into muscle. is sufficient, but not necessary, as this works with myf5 as well
What is the technical name of something that promotes differentiation into muscle?
myogenic factors
Pax6
induces differentiation into eye tissue
How can you study transcriptional regulation without changing the gene’s natural function?
Fuse the regulatory DNA associated with a gene to a “reporter” e.g GFP
Splicing
taking specific exons out of the nRNA , can make many combinations.
5’ cap
translatability
3’-UTR
mRNA localization, regulation of translation
