Summary of Immunostaining Results in Wild-type and Mutant Mice.

Host #: R = rabbit; GP = guinea pig. Wild-type mice were perfused at the time of expected peak of immunostaining (ZT12 for PER1 and PER2; ZT0 for BMAL1), and at the expected low point (nadir) of immunostaining rhythms (ZT0 for PER1, PER2, and ZT12 for BMAL1). Mutant mice were examined at the time of peak staining in wild-type mice. Results from wild-type mice at peak time are reproduced from Table 1, for comparison. CLOCK immunostaining was comparable at ZT12 (arbitrarily called Peak Time) and ZT0 (arbitrarily called Nadir Time). CLOCK-deficient mice were examined at ZT12. N = number of animals tested. Results are scored as described in Table 1: −(no SCN cells labeled), +(relatively poor staining), ++(good staining in SCN), and +++(best staining of SCN cells compared to background). NS indicates non-specific staining (cells inside and outside the SCN were labeled with the same intensity).