The DrosDel deletion kit is being constructed using RS (re-arrangement screen) P-elements originally constructed and described by Golic and Golic (1996).

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Balancing Stocks

RS lines were balanced using FM7h, SM6a and TM6C (eyD or ciD for chromosome 4). Most RS lines are homozygous viable, but occasional balancer flies may still be found in the stocks. A small proportion of RS lines are homozygous lethal or sterile.

Deletion (ED) lines were also balanced using FM7h, SM6a and TM6C. In the cases where this is a lethal or sterile combination we have tried various other balancers; the stocks that you receive from Szeged stock centre will be labelled accordingly. Some chromosome 3 deletions were balanced over TM2. This is a poor balancer for large regions of the chromosome and consequently the isogenetic characteristics of the stock will have been compromised to some extent.

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Making deletions with RS elements

The chromosomal forms of P{RS3} and P{RS5} contain a functional white gene (w^hs) and differ by the position of the two FRT (flipase recombination target) sites, which are shown as arrows in the diagram. Use of FLP-mediated excision produces the chromosomal remnant form of the element (P{RS3r} or P{RS5r}), which contains one non-functional portion of the white gene and one FRT site. FLP-mediated recombination between an RS3r and RS5r element will result in a reconstituted functional white gene with two 3’ P ends P{3'.RS5+3.3‘}. If the two elements are in trans on the same chromosome arm and in the correct orientation with respect to each other and to white, then a deletion of the chromosome material between the sites will occur. If the elements are close enough together and this event happens in the germ line, then red-eyed progeny will carry a chromosomal deficiency of defined length

Details of the RS element end sequence and primer locations can also be found here

References