UW FMR MOLB Week 5

primase

DNA-dependent RNA polymerase for lagging strand Okazaki fragments

sliding clamp (Proliferating Cell Nuclear Antigen)

keeps polymerase from falling off DNA

topoisomerase

relieve DNA supercoiling

topotecan

blocks topoisomerase (results in genome fragmentation → cell death)

dyskeratosis congenita

telomerase dysfunction; mutations in TERT, TERC → graying hair, skin degeneration, bone marrow failure

origin licensing

MCM complex initiates replication at one OriC and immediately degrades

direct reversal of DNA damage

dealkylation (suicide repair proteins)

base excision repair

replaces single base mismatches (C→U, mC→T)

nucleotide excision repair

detects and replaces “bulky lesions” (UV dimerization of adjacent Ts)

xeroderma pigmentosum

severe photosenstivity due to defects in nucleotide excision repair

mismatch repair

mutS pathway recognizes slippage and repairs

non-homologous end joining

double-stranded break repair; quickly joins broken DNA ends backtogether

homologous repair

double stranded break repair; highly accurate repair system that uses template (can result in repeat expansion)

microdeletion syndrome

results from homologous repair of similar but nonhomologous regions

G0 phase

terminated cells withdraw from cell cycle

G1 phase

RNA and protein synthesis

S phase

DNA synthesis

G2 phase

RNA and protein synthesis continue (no DNA synthesis)

M phase

mitosis and cytokinesis

G1/S checkpoint

restriction point: cellular environment must be favorable for replication

S checkpoint

checks for DNA replication errors or damage

G2 checkpoint

checks for completion of DNA replication

M checkpoint

spindle checkpoint (APC/C will unpin chromatids)

Rb

brake on cell cycle progression

p53

activates p21

BCL2

prevents apoptosis

BAX/BAK

promotes apoptosis (forms channel in mitochondrial membrane)

amyloid is found

in between cells

tau is found

in cells