Figure 2. CKI-1-Induced G1 Arrest Rescues Invasion in
nhr-67-Deficient ACs(A) Confocal sections of cell-cycle GFP reporters in wild-type (top) and
nhr-67(RNAi)-treated animals (bottom).(B) Epifluorescence smFISH images depict localization of
cki-1 transcripts (grayscale, top and red in overlay, bottom), nuclei (grayscale, second row and blue in overlay, bottom), and an AC-specific reporter (
lin-3>NLS-GFP, grayscale, third row and green in overlay, bottom). The AC in the
nhr-67(RNAi)-depleted animals is undergoing mitosis and thus lacks DAPI staining and an intact nucleus. Thus, the NLS-GFP is present throughout the cell. The white lines indicate the position of the AC and the dashed yellow lines indicate the position of the AC nuclei.(C) Quantification of
cki-1 mRNA transcripts per AC by smFISH (n > 10 animals examined for each, *p < 0.002, by a Student's t test, and error bars represent SEM).(D) DIC micrographs (left) and corresponding confocal sections of BM (laminin::GFP, middle) and an AC-specific F-actin probe (
cdh-3>mCherry::moesinABD, right) at the normal time of AC invasion. An
nhr-67(
pf88) animal has two ACs (arrowheads) that fail to invade (top). Induction of G1-phase arrest (
cdh-3>CKI1::GFP, second row) blocked cell division and rescued BM invasion (arrows). Induction of S phase arrest (hydroxyurea, third row) or G2-phase arrest (
cdk-1(RNAi), bottom) blocked AC division and division of uterine cells (*), but did not rescue invasion (intact laminin::GFP, middle).