number of cells required to clone an animal
one
transcripitionally active chromatin
euchromatin
region that controls gene transcription
regulatory region
transcriptionally inactive
heterochromatin
regulatory regions control genes in this manner
turn genes on and off
stretches of Dna of defined sequences
cis-acting
regulatory proteins bind to this part of the helix
major groove
gene regulatory proteins that recognize cis-acting
trans-acting
structural motifs on gene regulatory proteins recognize these
DNA sequences
most common and simplest motif
helix-turn-helix
subclass of helix-turn-helix
homeodomain
motif in which two alpha helices are joined together in a short coiled-coil structure
leucine zipper
describe zinc finger motif proteins
alpha helices and beta sheets coordinated by zinc atoms
creates homodimes and heterodimers
helix-loop-helix motif
name two gene switches
lac operon and tryptophan synthesizing operon
exampe of repressors and activators working together
lac operon in E.coli
number of gene regulaotry proteins in eukaryotes
thousands
DNA sequence where the general transcriptioin factors and polymerase aseemble
promotor
regulatory sites that are distant from the promotor
enhancers
gene regulaotry proteins consist of two domains
structural motif and activation domain
repressors work in these 2 ways
inactivate transcription factors and change chromatin
ways activity of gene regulaaotyr proteins are regulated
proteins synthesis, ligand binding, protein phosphorylation, addition of second subunit, unmasking, stimulation of nuclear entry, release of membrane
group of proteins that form together on an enhancer to regulate transcription
enhanceosome
DNA sequeces that prevent regulaotyr proteins form influencing distant genes
insulators
example fo set of genes coordinated by single protein
glucacorticoid receptor
clonl inheriatnce fo a condensed inactive X chromosom in female mammals
x-inactivation
heritable, reversible changes in the genome that regulate gene expressoin
epigenetics
effect of methylation on some genes
allows other proteins to bind nad gene shut down
how methylation causes cancer
shutting down tumor suppressor genes
def of imprinting
diff. expression fo a gene allele depending on parental origin
splice variants linked to these diseases
breast cancer and thalassemias
name 3 extracellular signals
peptide horomons, growth factors, lipid soluble steroid horomones
sufficient cellular iron has this effect on trasnferrin receptor
degradation
proteins involved in the active transport of mRNA out of nucleus
hnRNA binding proteins
RNA that silence viral gene expression
miRNA, siRNA, lincRNA
low cellular iron prevents this
mRNA degradation
20% of human genes encode these
antisense mRNA
Fragile X
x-linked disorder cause of common form of retardation
binds and sequesters intracellular iron
ferritin
low iron requires cells to do this to ferritin production
shut down
addition of a carbohydrate
glycosylation
kinase make protein active or inactive vis this
phosphorylation
lipid modifications target a protein to this structure
membane
can unmask a functional unit of a protein
cleavage
effect of (+) lactose ins lac operon
no repressor
effect of (+)glucose in lac operon
no cap
situation where operon is on
(-) glucose (+) lactose, cap on, reperessor not bound