Figure 1.

Molecular Circadian Clockwork within SPCs

Twenty-four-hour oscillations in core clock components BMAL1 and CRY1 were present at the transcriptional and protein level.

(A) Forty-eight-hour analysis of mRNA using qRT-PCR (p < 0.001 for BMAL1 and CRY1; n = 4 independent experiments).

(B) One-hundred-hour analysis of mRNA using bioluminescence reporters (p < 0.001 for BMAL1 and CRY1).

(C and D) BMAL1 and CRY1 protein expression during 48 hr. Counter phased 24-hr rhythms were present (p < 0.001 and p = 0.014 for BMAL1 and CRY1, respectively; n = 4 independent experiments).

(E and F) BMAL1 protein expression during 48 hr. Twenty-four-hour rhythmicity was absent when SPCs were unsynchronized (p = 0.734; n = 4 independent experiments). Presence of rhythmicity was independent of synchronizer substance (forskolin p = 0.01; n = 4 independent experiments) and high/low proliferation rate (proliferating cells p = 0.002; n = 4 independent experiments).

Data are presented as mean ± SEM; ^∗p < 0.05 for significant 24-hr oscillation. See also Figure S2.