Transposition Flashcards
transposons (def.)
mobile segments of DNA that can hop or transpose from one place in DNA to another
transposition was documented in _____ Barbara McClintock in corn
1950s
transposition is not like ________ (___ independent); does not require lots of_____ DNA
-homologous recombination
-RecA
-homologous
Transposons exist in ___ organisms; they indirectly move between different genera of _____; transposition occurs from _______ to ____ cell divisions and is _____ regulated
-all
-bacteria
-1/10^3 to 1/10^8
-highly
Transposition is a way of introducing genes from one bacterium to another where ______
little DNA sequence homology exists
Two types of transpositions
1) Conservative or “Cut and Paste” Transposition (one copy before and after transposition)
2) Replicative Transposition (One or two copies of transposon in DNA after; site specific recombination)
There are many different types of transposons; all transposons contain ______ sequences at their _____ encode a ______ internally that mediates transposition. all transposons are bracketed by ______ surrounding tranposon (a consequence of transposition)
-inverted repeat
-ends
-transposase (tnp)
-short direct repeats of target DNA
3 types of transposons
1) Insertion Sequence Elements
2) Composite Transposons
3) Non-composite Transposons
Insertion Sequence Elements are _____ transposons; 750-2000 bp. have _____ at ends, _____ enzyme and ______. almost all bacteria carry IS elemnts; ___ carries several. Eg. ___
-smallest
-inverted repeats
-transposase
-regulators
-E.coli
-IS3
IS3 was og detected as mutation in ___ genes with funny properties which were ____ (4)
-gal genes
-highly polar, cannot be induced to revert
-galactose utilization gal plasmids transferred to gal-mutants acquire mutations with similar characteristics
-these mutated plasmids are larger than wild type counterpart
Non-composite Transposons have ______ on ends (not IS elements), ______, regulator of ____, and _____ genes
- short inverted repeats
-tranposase
-transposase
-other (AbR)
Composite Transposons are 2 IS elements in ______ orientation which bracket other genes & encode _____
-same or opposite
-antibiotic resistance determinants
flanking IS elements from a composite Tpn can transpose ______ or with the ______
-individually
-entire composite transposon
composite transposon insertions in a
plasmid -> ________ can be used to transpose the plasmid DNA
inside inverted repeats
assays of transposition
1) suicide vectors
2) mating out assay
3) hybridization analysis