FIG. 5.

(A) Analysis of fibrillarin expression in Fibrillarin^+/− embryos. Heterozygous males were mated to heterozygous females to determine fibrillarin gene expression during mouse development. Fibrillarin expression, as measured by β-galactosidase activity, is ubiquitous until 11.5 dpc, when the expression pattern became more restricted to highly proliferating tissues such as neural tube and limb buds. (B) Hematoxylin- and eosin-stained wax sections of testis, skin, liver, and intestine from wild-type (+/+) and heterozygous mutant (+/−) mice. Magnification, ×20.