Regulation of Gene Expression Flashcards
double minutes
forms during gene amplification as regions of a chromosome undergo repeated cycles of DNA replication
small unstable chromosomes that lead to amplification of genes involved
transcription regulation by steroid receptors
hormone response elements bind the hormone receptor to affect transcription
constitutively activated
describes genes that are regulated solely by DNA consensus elements in the promoter region
extracellular signal transcription activation
protein recetprs such as G-proteins
activation of a cytoplasmic transcription factor
transcription factor kept out of the nucleus when inactivated
TATA-binding protein0associated factors (TAFs)
tissue specific and gene family specific activators or repressors of transcription
do not bind DNA, often histone acetylases or deacetylases
four types of alternative splicing
exon skipping, mutually exclusive exons, alternative 5’ donor or 3’ acceptor sites, intron retention
cryptic splice sites
can arise from mutations, creating frameshift mutations, premature truncations, insertions, or deletions
alternate polyadenylation sites selection
having an earlier polyA site or changing the length of the 3’UTR can truncate genes or change the regulation of genes
regulation through RNA export
transport factors help export mRNA, these factors are limiting and are recycled once the RNA has been exported
transcription stops if these packaging proteins run low
long non-coding RNAs
look like mRNA but do not have open reading frames due to high frequency of stop codons
may bind to mRNA to regulate processing or stability, some lncRNAs regulate chromatin structure
internal ribosome entry site
sequences form secondary structure in the mRNA that allows translation to initiate internally in an mRNA in a cap-independent mechanism
involves eIf4G/4A complex
regulation of globin mRNA translation by heme
in RBCs, high heme activates globin translation and low heme represses globin translation
iron-response element binding protein (IRE-BP)
binds to the iron response element (IRE), which is a hairpin loop on both transferrin and ferritin proteins
when iron is high IRE-BP is inactivated and ferritin is translated
when iron is low IRE-BP is activated and transferrin is translated
exosome complex
the nuclease complex that degrades mRNA and non-coding RNAs
