MARIA - LECTURE 1 Flashcards
what does the switch between the on and off state of genes depend on
- chromatin remodelling
- transcription factors
- RNA polymerase II
why do we look at transcription at the single cell level
not all cells have active TS sites simultaneously
not all transcription sites have the same number of polymerase II
what are the two possible models of transcription and what is the most common way in which transcription occurs?
how do visualise transcriptional burst in live cells
what is the telegraph model of transcription
exact regulation of transcription by TFs based on the concentration, duration and strength
how do transcription factors regulate the output of transcription
how long until a interaction between a TF and DNA is meaningful
becomes a meaningful interaction after 3-4 seconds
relative ease of turning transcription on and off
when does mRNA processing happen
happens at the same time as transcription
the mRNA is never naked in the nucleus or in the cytoplasm
different sets of proteins depending on the location, but never naked
what are the four major steps in the nuclear export of mRNAs
what is mRNP
Messenger ribonucleoprotein
mRNA and protein complex
mRNPs carry instructions to export cargo mRNA into the cytoplasm from the nucleus
what are the 5 classes of proteins involved in nuclear export of mRNA and what do they do
what is the first step of nuclear export
what is the TREX complex
where is the TREX complex added
added to the 5’ end of the mRNA through interaction with the cap binding complex (CBC)
assembled during transcription and splicing using ATP
what are the components of the TREX complex
what are SR proteins
what do the phosphorylation states of SR proteins do
how does splicing act in the first step of nuclear transport
how are intronless mRNAs (histone or yeast mRNAs) exported?
how do transcripts move from their site of synthesis to their nuclear exit point? (step 2: transcripts are reaching the NPC)
what is step 3 of mRNA export
in which orientation does mRNA leave the nucleus
first the cap and then the poly A tail end
structure of the NPC
what are the four steps of exit through the NPC and the timing
docking: 80ms
transport: 5-20ms
release: 80ms
how does step 4 of mRNA export happen
the additional step: export receptors shuttle back to the nucleus
diagram of how disassembly of adaptors happens
