Egg chambers with defective oocyte determination in
γTub23CPI fs(2)TW1RU34 mutant females.
Egg chambers from WT (A, E, and I) or
γTub23CPI fs(2)TW1RU34 (B-D,
F-H, J-L, and M-P) females stained
for DNA (gray in A-D, F, K, and L; red in E,
H, and M-P), ring canals (gray in G, green in
E and H) and microtubules (green in M-P).
Posterior is to the right. (B-D) One of the two oocyte-like
nuclei found within these egg chambers is always located posterior
(arrowhead), as in the WT (A). The second oocyte-like nucleus (arrow)
can be found anywhere within the egg chamber, posterior (D), anterior
(C), or in the middle (B). It may have undergone a few
rounds of endoreduplication in D.(F-H) One of the
oocyte-like nuclei of this egg chamber is located posteriorly (arrowhead)
within a cell with four ring canals (only two are visible). The oocyte has
four ring canals in the WT (E). There are two more oocyte-like nuclei
in the mutant egg chamber (arrows), located in cells with only one ring canal.
H is a merge of F and G. (I and
J) In situ hybridizations to osk mRNA. In the
mutant (J) most signal is located within the posterior oocyte,
similarly to what observed in a WT egg chamber (I), but there is also
some accumulation of osk mRNA associated with the second oocyte-like
cell (arrow in J). K and L are different focal
planes of the egg chamber shown in J, stained with DAPI, to indicate
the position of the oocyte nucleus (arrow in L) and the second
oocyte-like nucleus (arrow in K). (M-P) Two
examples of microtubule organization in 14 + 2 egg chambers at midoogenesis.
N and P are higher-magnification images of the areas within
the white boxes in M and O, respectively. In the egg chamber
in M microtubules seem to accumulate around the second oocyte-like
nucleus (N). No clear accumulation of microtubules close to the
second oocyte-like nucleus can instead be detected in O and
P. All images were obtained with conventional fluorescence
microscopy, except E and M-P, which are confocal
images, and I and J, which were obtained with phase-contrast
microscopy. Egg chamber size is ≈150 μm.