control of eukaryotic expression 1 Flashcards
what enzyme causes differentiated gene expression?
rna polymerase II
what is a transcription factor ?
protein with a specific modular structure nd dinstinct binding domain which can bind to DNA sequences to control transcription rate
what does RNA polymerase 1 transcribe?
some genes encoding ribosomal RNA genes
what does RNA polymerase 2 transcribe?
all protein coding genes and some non-protein coding genes
what does RNA polymerase 3 transcribe?
all trna genes and some rrna genes and other small rna genes.
what are housekeeping genes and what do tey carry out?
they are genes expressed in all cell types
encode RNA and protiens required for universal cell function. such as metabolism, cell survival, dna repair and protein synthesis
why might levels of housekeeping genes vary?
depends on rate of tissue growth and proliferation and nutrient availibilty
how is transcription control exerted (trans and cis)
trans acting transcription factor binds to cis acting dNA sequence next to gene
how does transcription initiation begin?
binding of general transcription factors (GTFs) to TATA box in promoter region of DNA
what do GTFs do?
distort promoter region of DNA to allow binding of RNA polymerase II to trancription initation site
can transcription take place with out transcription initaition complex?
NONONONONO
TIC - GTFs to TATA box in promoter region + binding of RNA polymerase 2 to TIS
what does in vivo transcritpion activation also require?
transcription activators and auillary proteins
what in antp and what does it promote?
antennapedia transcription factor is sequence specific DNA binding protein that regullates transcirption via interactions involving TIC (cause antennae to formon head of drosophila)
what is Gli3?
rabscription factor involved in H that reguatesdigit number
what is cycloidia and what does it promote?
transcirption factor that promotes bilateral symmetry of snapdragon flowers
