Reexamination ofGeneTargeting Frequency as a Function of theExtent ofHomologybetweentheTargeting Vectorand theTarget Locus

The invention relates to a supporting frame with a base unit comprising a compartment at least for partial reception of the housing of the lifting column (79) and a cross member (74) for mounting on the base unit (59). The supporting frame comprises a locking element (94), which when placed in-a locked position exerts a squeezing force between the base unit (59), the lifting column housing and the cross member (74), by which the lifting column housing and the cross member (74) are fixed in the base unit (59). The supporting frame further comprises means for retaining the locking element in the locked position. The lifting columns are of the type, which comprises telescopically arranged profiles with an upper and lower end to which upper end a housing is secured.