Fig. 3. Rac1Leu61 is associated with markedly widened villi in adult chimeric mice (A) Idealized three-dimensional drawing of the mouse small intestine from a normal C57Bl/6-ROSA26
129/Sv mouse. The front of the intestine has been 'sectioned’ to show the relationship of individual crypts and adjacent villi. In the adult chimeras, crypts are ‘monoclonal’: composed of either B6-ROSA26 or 129/Sv epithelial cells, but not a mixture of both. Some villi are ‘polyclonal’: supplied by crypts of both genotype. (B) Whole-mount preparation of jejunum from a 9-month-old normal chimeric mouse. The intestine has been opened, fixed and stained with X-Gal. The white epithelium is 129/Sv. The blue epithelium is composed of B6-ROSA26 cells that express lacZ. (C) 9-month-old Rac1Leu61chimeric jejunum prepared as in B. Compared with the normal 129/Sv villi in B, 129/Sv-Rac1Leu61 villi are widened, in some cases coalescing to form very unusual, undulating, slab-like structures (arrowheads). The arrows point to sharply demarcated stripes of blue cells that emanate from B6-ROSA26 crypts supplying two widened polyclonal villi. The inset shows the results of a RT-PCR analysis of normal and Rac1Leu61 RNAs. The 250bp PCR product is from the Fabpl-Rac1Leu61 transcript. Scale bars: 235 µm.
