Mice that are homozygous for the targeted mutation are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. No gene product (protein) is detected by Western blot analysis of whole brain minus cerebellum and hypothalamus, whole hypothalamus, and anterior hypothalamus containing SCN, from homozygotes. Immunoprecipitation analysis of brain lysates from homozygotes does not detect any gene product (protein). Abberant gene products (mRNA) are detected by Northern blot analysis and RT-PCR, and have rhythmic expression. Under conditions of constant darkness, homozygous males exhibit a shorter free running period. A subset of mice exhibit progressive shortening of the period length in extended constant darkness. This mutant mouse strain may be useful in studies of circadian rhythm and sleep patterns.
Please note: Mice derived from 129S-Per3tm1Drw/J are reported to a carry a spontaneous deletion in exon 3 of the Mfrp gene (174delG or rdx) that causes photoreceptor degeneration and eventual retinal pigment epithelium. It is unknown if the Per3 KO carries the mutation. (IOVS 2011 52(10):7256)
