Exam 3 Flashcards
SWI/SNF
remodel nucleosomes and core histones within chromatin, making DNA more accessible for transcription
Receptor that forms a tertiary nuclear complex with HDACs
RAR (retinoic acid receptor)
add methyl groups to DNA; reduces transcription and condenses chromatin
HMTase (histone methyl transferase)
RNase II
cuts each nucleotide on the 3’ tRNA first
histone fold
helix-loop-helix-loop-helix motif
transfer acetyl groups (COCH) from Acetyl-CoA to lysine residues on histone tails; loosens chromatin
HAT (histone acetyltransferase)
remove acetyl groups from histones to repress gene expression
HDAC (histone deacetylase)
RNase P
cuts tRNA 5’ end in one step to yield mature 5’ tRNA product following RNase III cut
-composed mostly of RNA with small proteins; requires Mg2+
facilitates poly(A) elongation through PAP stabilization in the second phase of polyadenylation (~250 As)
-49kD protein, enhanced by but not requiring CPSF
PAB II (poly(A)-binding protein II)
helix 2 (splicing)
formed from the 5’ end of U2 interacting with the 3’ end of U6 to help orient the snRNPs during splicing
remodel nucleosomes and core histones within chromatin, making DNA more accessible for transcription
SWI/SNF
cuts tRNA 5’ end in one step to yield mature 5’ tRNA product following RNase III cut
-composed mostly of RNA with small proteins; requires Mg2+
RNase P
segments of noncoding DNA that recruit DABPolFEH
control elements
Guanylyl transferase
attaches GMP to the 5’ end of the RNA
26S RNA
group 1 intron that exhibits ribozyme activity driving recognition, splicing, and product formation (lacks lariat structure)
PNPase
(polynucleotide phosphorylase)
removes phosphates on 3’ end of tRNA (2+ from end) following RNase II cutting; requires ATP
Prp28 (protein)
works with U6 to displace U1
methylates guanine at position 7 (terminal nucleotide) of cap
methyltransferase
RNase III
cuts precursor tRNAs to generate free 5’ and 3’ ends
HP1
binds methylated histones to block gene expression
splicing: step 2
guanosine hydroxyl group attacks (2nd) intron-exon phosphodiester bond, linking exons and resutling in intron release
recognizes precursor tRNA and cuts out intron
tRNA endonuclease
activator binds before H1 or moves nucleosome, triggering gene expression (makes DNA more accessible to transcriptional machinery)
antirepression
corepressor that forms a tertiary nuclear complexes with HDACs
SIN
antirepression
activator binds before H1 or moves nucleosome, triggering gene expression (makes DNA more accessible to transcriptional machinery)
helix-loop-helix-loop-helix motif
histone fold
MSK1
(mitrogen-and-stress-activated kinase)
phosphorylates nucleosomes next to a methylated amino acid to enhance transcription
HAT
(histone acetyltransferase)
transfer acetyl groups (COCH) from Acetyl-CoA to lysine residues on histone tails; loosens chromatin
tRNA endonuclease
recognizes precursor tRNA and cuts out intron
removes phosphates on 3’ end of tRNA (2+ from end) following RNase II cutting; requires ATP
PNPase (polynucleotide phosphorylase)
82kD protein with RNA-binding domain (RBD), polymerase module, 2 nuclear localization signals (NLS), & 2 serine/threonine-rich regions
PAP (poly(A) polymerase)
binds methylated histones to block gene expression
HP1
Slu 7
required for 2nd step of splicing (completing formation of mature mRNA)
-reads the AG phosphodiester bond of the intron and first nucleotide of exon 2 (3’ splice site)