(Downloading may take up to 30 seconds.
If the slide opens in your browser, select File -> Save As to save it.)
Click on image to view larger version.

Fig. 8. ATH5 expression is upregulated during the last S phase. (A) Retinal cells
isolated at stages 22-23 and 28-29 were transfected with an
ATH5-promoter/lacZ-reporter plasmid singly or in combinations with
NGN2 or ATH5 expression vectors and pulse-labelled with
[3H]-thymidine at the end of a 24-hour culture period. (Left) The
number of lac+ cells counted when the reporter plasmid was
transfected alone is set at 1. (Right) At stage 22-23, overexpression of NGN2
enhances promoter activity in proliferating cells (a) and increases the pool
of nonradioactive cells whose ATH5 promoter is upregulated (b). At stage
28-29, lac+ cells whose promoter is strongly upregulated
are unlabelled (d). The detection of double-labelled cells (c) and their
increased number upon ATH5 overexpression indicate that ATH5 promoter activity
is upregulated during the S phase. (B, left) A retina at stage 29-30 was
pulse-labelled for 45 minutes with BrdU and chased for 15 minutes. Transverse
sections were hybridized with an ATH5-specific riboprobe. Most BrdU-positive
cells are in S phase and their nuclei are located on the vitreous side (vi) of
the pz. ATH5 transcripts accumulate on the ventricular side (ve) of the pz in
the region where cells are in the G1 and G2 phases of the cell cycle. A few
BrdU-positive nuclei are located in this region (arrowheads). (Right)
Schematic of mitosis in the pz. Scale bar: 40 µm.