roo element is inserted in exon 9a, 35bp 3' of the exon 9a 3' splice site, and is flanked by a 4bp target site duplication. The element is orientated such that they contain a consensus polyadenylation signal, which includes the canonical AAUAAA element, and a GU rich domain within 50 nt 3' of the cleavage site.
Duplicated copy of Mhc present on Dp(2;3)osp3 is sufficient to rescue lethality.
Mogami.