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Fig. 2. Kidney development in Six1-deficient mice. (A-D) Metanephros (mt)
in Six1+/- (A,C) and Six1-/- (B,D)
mice at E12.5. Kidneys are absent in Six1-/- mice
(*), but ureter (ur) was observed in the left primordium (D). The
genital tracts appeared to be normal both in males and females. (E) In
Six1+/- embryos of E11.5, ureteric bud (ub) grows out from
Wolffian duct and invades the mesenchyme and the metanephric mesenchyme (mm)
are condensed around the bulging ureteric bud. (F) In
Six1-/- embryos, although the ureteric buds grow out from
Wolffian ducts, they fail to invade the mesenchyme (arrows) completely. (G-J)
TUNEL analysis of metanephros in Six1+/- and
Six1-/- embryos at E11.5. Note the apoptotic cells were
markedly increased in Six1-/- metanephric mesenchyme
(arrows). g, gonad; wd, Wolffian duct.