[Mutant gene expression in mouse aggregation chimeras. 2. The dominant cataract-FR gene]

An analysis of dominant cataract-Fr (CatFr) gene in chimaeric mice CatFr/CatFr c/c in equilibrium +/+C/C has shown that CatFr gene is active in the differentiation lens fibres. The pycnosis of nuclei was observed in the primary lens fibres both in 14 day old chimaeric and CatFr/CatFr embryos. In the central part of lens of the 17 day old chimaeric embryos, there are, besides the fragmented pycnotic nuclei, nuclei with normal morphology which are not observed in CatFr/CatFr embryos. The pycnosis of nuclei was observed in some deep cortical lens fibres of both 17 day old chimaeric and CatFr/CatFr embryos. In the newborn chimaeric mice practically all centrally located lens fibres had destructive changes. The effect of gene CatFr, pycnosis of nuclei, was used as cell marker in clonal analysis of lens development. The count of pycnotic nuclei in the primary and secondary lens fibres of, respectively, 14 and 17 day old chimaeric embryos has shown a high degree of correlation in the ratio of normal and mutant cells between the left and right eye lenses. A high degree of correlation was also established in the ratio of pigmented and unpigmented cells in the retinal pigment epithelium between the left and right eye. A positive correlation was also shown in the ratio of mutant and normal cells between the lens and retinal pigment epithelium in both 14 and 17 day old chimaeric embryos.