In this strain, a neomycin phosphotransferase resistance (neo) cassette replaces the entire coding region of the endogenous mouse activating transcription factor 4 (Atf4) gene, abolishing gene function. Mice homozygous for the Atf4 allele exhibit low viability, with delayed bone formation during embryonic development and low bone mass throughout postnatal life. They exhibit a reduction in oxidative stress-induced gene expression, resistance to oxidative death, and decreased consumption of the antioxidant glutathione. They also have decreased insulin sensitivity, smaller fat pads, and delayed hair growth as compared with control mice. Adults are severely microphthalmic, with no recognizable lens, anterior chamber, iris, or vitreous body. These mice may be useful for studying cell proliferation defects associated with blindness, osteoporosis, and stress responses.
