[Tissue-specific expression of the chimeric gene delta KpF in transgenic mice]

The expression of the chimeric gene delta KpF in which the promoter region of delta-crystallin gene was replaced with the long terminal repeats (LTR) of Friend spleen focus forming virus (SFFV) was studied in transgenic mice for approaching the regulatory mechanism of the expression of chicken delta-crystallin gene. The recombinant plasmid (p delta KpF) DNA containing delta KpF gene was microinjected into male pronuclei of fertilized mouse eggs. The injected eggs were implanted into the oviducts of pseudopregnant female mice and allowed to develop to term. Subsequently, 35 mice from those eggs were born. The mice were analyzed at 2 weeks of age with respect to gene integration and expression by the method of DNA blot hybridization and immunoenzymologic assay. DNA-DNA hybridization indicated that the genomic DNA from one of the mice retained the sequences that hybridized strongly with the probe, p delta KpF. Enzyme linked immunosorbent assay (ELISA) showed that delta KpF gene was expressed in the lens, but not in the brain, muscle and liver. These results demonstrate that the essential regulatory elements for tissue-specific expression of chicken delta-crystallin gene reside in the sequences downstream from +677bp.