transposable elements and DNA repair

Who discovered jumping genes

barbara mcclintok

transposable genetic elements

can move from one site to another site

transposable genetic elements can alter

phenotypes when they move

AC

activator

AC ACTIVATOR IS

a complete transposable element with functional transposase and repeats

DS dissociation is

lacking functional transposase gene so it requires the AC transposase to move

transposons have the potential to

move regulatory sequences to new places which could affect gene expression

arabidopsis transposon

transposase derived proteins regulate plant genes required for plant growth

in bacteria what repairs pyrimidine dimers

photoreactivation repair

describe photoreactivation repair

enzyme photolyase absorbs light and clips dimer

methyltransferase restores

correct form to iccorecely methylated guanine bases by remocing methyl group

proofreading during replication is used to

repair mistakes during replication via DNA polymerase

in proofreading, _______ from the DNA polymerase remove incorrect nucleotides and then _______ inserts the correct nucleotides

exonuclease, DNA polymerase

in Ecoli methylation

distinguishes old from new dna

missmatch repair proteins

recognize abnormal helical structure and id the incorrect base

exonucleases

remove an area of the new strand from the methylated sequence to this mismatch

DNA polymerase

fills the gap and ligase seals the nick

base excision repair

removes modified bases

Glycosylases

reconginize and remove defective bases resulting in an AP site in B.E.R

AP endonuclease cleaves the phosphodiester bond next to the

missing base and then removes the rest of the nucleotide

homologous recombination repair

uses sister chromatid to repair the break

nonhomologous end joining

joins broken ends and can lead to translocations, deletions, and insertions

Translesion DNA Polymerase are

specialized polymerases that can bypass lessions on the DNA during replication. but they often make errors

xeroderma pigmentosum

due to faulty nucleotide excision repair of thymine dimers