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w_hite
Nuovo Arrivato
22 Messaggi |
 Inserito il - 10 ottobre 2011 : 18:06:31
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Salve a tutti...ho veramente difficoltà a comprendere questa figura(che ho allegato) con relativa didascalia,che tra l'altro è in inglese sul sistema FLP/FRT...ovviamente non chiedo la traduzione letterale di tutto ciò,ma per favore vorrei che mi aiutaste a capire perchè mi risulta davvero complicato :(...
Flp recombinase mediates site-specific recombination between FRT (Flp recombinase target)sites during replication of the yeast 2#956; plasmid, and works very efficiently when expressed in Drosophila. Flp-mediated recombination can be used to generate mitotic clones by creating flies with transgenic FRT sites at identical positions on homologous
chromosomes98. If the site-specific recombination between homologues occurs after DNA replication, and the daughter chromatids segregate appropriately, the region of the chromosome arm that lies distal to the FRT site will be made homozygous,with each daughter cell inheriting two copies of this region from one of the parental chromosomes (see figure). This site-specific recombination event can be used to make a mutagenized chromosome arm (red) homozygous in clones of cells,which can then be screened for a phenotype. The principal advantages of this approach are: first, F1 screens can be carried out for recessive loss-of-function phenotypes, as there is no longer a need to go through two additional generations to make the mutagenized chromosomes homozygous, as is the case in a traditional genetic screen; and second, by controlling where and when the
recombination occurs, only the cells of interest are made homozygous. The tissuespecific phenotypes of mutations in essential genes can therefore be identified, regardless of their other functions in development. One disadvantage is that Flp/FRT screens cannot detect mutations that lie proximal to the FRT site.However,FRT insertions have been recovered close to the centromere on all of the main chromosome arms, and it is now possible to screen ~95% of the euchromatin, although this requires carrying out separate screens for each of the five arms.
Allegato:  FLP-FRT.pdf
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w_hite
Nuovo Arrivato
22 Messaggi |
Inserito il - 11 ottobre 2011 : 12:22:22
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| Vi scrivo quello che penso di aver capito...I siti FRt sono stati inseriti vicino al centromero in modo tale che una ricombinazione tra due omologhi FRT,che hanno quindi lo stesso FRT nella stessa posizione,possa far scambiare il braccio di cromosoma...per cui fornendo la flippasi FLP si possono far ricombinare i 2 cromosomi omologhi facendo una ricombinazione mitotica... |
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