Sequence encoding part of the Fab-7 boundary element has been inserted into the attP site present in TI{TI}Fab-7attP50, reconstituting a mutant Fab-7 element that lacks the HS1 nuclease-hypersensitive region (deletion coordinates are 3R:16898915..16899283 , release 6 genome). A loxP site and an FRT site are present downstream of the inserted sequence.