ch 19 Flashcards
Cis-acting regulatory elements:
-DNA sequences located on the SAME DNA molecule as the gene they control
-allow basal-level transcription (basic level)
Trans-acting regulatory elements:
- can come from different chromosome
- They have the ability to inhibit or activate gene expression depending on their role and where they are binded to
what are the types od transcription factors?
-Basal transcription factors:
-Activators:
-repressors
what can basal transcription factors do?
they can bind to promoter regions and help in binidnig RNA polymerase to the promoter region.
what are Activators?
increase transcription
-: bind to the enhancer regions and enhance transcription above basal levels and so the DNA can bend if activators are bound to enhancer regions far away from the gene
Repressors
bind to specific DNA sites near the genes (sometimes enhancers) and prevent transcription initation
why are some transcription factors flexible?
they can act as both an activator and a repressor
Insulators
organize chromatin so that the enhancers have access to only particular promoters
where are insulators located?
in between promoters and enhancers to to block their interaction
what if the promoter is transcribed? or when an insulator blocks the promoter? what kind of effect do these have on the enhancer?
-If both promoters are transcribed then the enhancer region will act on these genes that are nearby it since enhancers are so far away from what they transcribe that they can activate nearby promoters
-An insulator can prevent one of the promoters so it doesn’t actually get translated
RNA processing
-alternative splicing creates different mRNA molecules from the same pre-mRNA transcript
-Unique to eukaryotes and adds a 5’ tail, slices it and makes exon mRNA
mRNA degradation
- mRNA transcripts are temporary and their stability relies on the alternation of the ends
=there can be a signal in the untranslated region that can control the lifespan
-caps at the ends stabilize it temporarily
