transposable elements Flashcards
class 1 transposable element
what kind of terminal repeats
what does it encode
how does it transpose
what 3 organisms have class 1 transposable elements
short
transposase
DNA
bacteria, animals, corn
class 2 transposons:
what kind of repeats
what does it encode
how does it transpose
what 3 organisms have thsi
long terminal repeats
reverse transcriptase
RNA intermediate
humans, animals, yeast
where does transposase cleave a transposon
at the terminal inverted regions
what causes the direct repeats seen at the ends of transposons
the staggered cleave that transposes makes. The staggered are compliments of each other and since one is on the bottom and one is on the top, when new DNA is synthesized it becomes direct repeats
4 steps of retrotranespositon
what is special about the end result of this process
transcribes and translates regularly
ribonucleoprotein does its thing
reverse transcription occurs
new inserts are added into the genome
the old inserts of the genome are still in tact. copy and paste
replicative transposition:
_____ recognizes ____ and cleaves them
also cleaves ____ ___
_____ attach
replication begins on the single strand _____ strand
is this the one in tact?
what is then made when the bubbles fuse together
______ _____ occurs of the structure so that both molecules get some of the transposon (this is also copy and paste)
transposes flanked repeats
also cleaves target side
free ends of both molecules attach
begins on the template strand
a + b coingate
crossing over
how does replicative transposition occur in bacterium
retrotransposition and coin gate transposition
what structurally happens that allows for conservative transposition
what chemistry event occurs that causes thsi to happen
what essentially happens
it loops out
dimerization
the transposon is looped out and floats to the region that it will be inserted into
what can give rise to multiple copies of a transposon
why
if a conservative transposon jumps somewhere before the replication fork reaches it
you are creating 2 copies, think top and bottom. If the top strand’s transposon jumps to the part of the DNA still in one fragment, there will be 2 transposons there when the strand splits (refer to pic)
for bacterial transposons
what is a transposon with transposase and inverted sequence
what is transposon with transposase and genes not related to transposing (jumping)
what is ^ flanked with
insertion elements (Is)
Tn elements
inverted Is elements
what is the difference between a Is and Tn
Tns have genes unrelated to transposition
for a Tn element, describe the structure
what is interesting about this
gene not with transposase directly in the middle and flanked by Is elements with inverted repeats
the entire outer edge is flanked with direct repeats where it will be cleaved
the transposases are inverted
difference between elements and sequences
sequences lack the direct repeats on the edges
what are gaps in the transposase gene called
deletions
