Fig. 3. Asp associates with the poles but not the central spindle of
dd4S spermatocytes. Asp localization (red) in
relation to microtubules (green) and DNA (blue) in meiotic wild-type (A-C) or
dd4S (D-F) cells. Wild-type cysts are shown at
prometaphase (A) and anaphase/telophase (B). Asp is localized at the spindle
poles (arrowhead in B) and in association with the tips of microtubules in the
central spindle during anaphase/telophase (arrows in B). (C) Later telophase
stage in which cells show pronounced constriction around the central spindle
mid-zone. Asp interacts with the putative minus ends of central spindle
microtubules, more distant from the poles at this stage (arrows and arrowheads
in the inset). The inset shows an enlargement of the spindle marked with small
arrowhead. (D) Cyst of dd4S cells apparently at
early meiosis with Asp staining at the centre of the hemi-spindle asters
(arrowheads). The arrows indicate cells attempting to organize a bipolar
spindle with defects in Asp distribution at the poles. The inset shows a
higher magnification of the distribution of Asp in a hemi-spindle. (E) Cyst of
dd4S cells in which the arrow points to a sharp
cone with Asp staining only at the astral pole. The arrowheads highlight
microtubule tips at the periphery of three hemi-spindles. Inset shows a more
detailed view of a cone with fibrous Asp-containing material emanating from
the astral pole and in this case also localizing near a central-spindle-like
bundle of microtubules. (F) dd4S cyst displaying
a anaphase cell lacking central spindle microtubules and with fragmented Asp
staining at the poles (arrow). The large arrowhead points to a fibrous
distribution of Asp emanating from the centre of a hemi-spindle aster. The
inset shows a higher magnification of the spindle indicated by the small
arrowhead showing a cone with some Asp localizing in the central-spindle-like
region. Bars, 50 µm. Bar in insets of D and E, 10 µm.