Fig. 4. PGCs derived from anterior pole cells preferentially associate with the nascent cap cells. (A,A') A late third instar larval ovary derived from an embryonic gonad containing a labeled anterior pole cell viewed under low and high magnification, respectively. The ovary, with the anterior pole up, is stained with anti-1B1 antibody (red) to outline somatic cells and spectrosomes in germ cells, and with anti-GFP antibody (green) to identify PGCs derived from the marked pole cell. Note that the PGC marked by an arrow is in direct contact with the base of two forming terminal filaments (TF). (B,B') A late third instar larval ovary derived from an embryonic gonad containing a labeled posterior pole cell viewed under low and high magnification, respectively. The ovary, with the anterior pole up, is stained with anti-1B1 (red) and anti-GFP (green) antibodies. Note that the PGC marked by an arrow is approximately six cells away from the base of the forming terminal filaments (TF). (C) Summary of the location of PGCs (green) derived from marked anterior or posterior pole cells (green). The fractional numbers at the lower right corner of each third instar larval or prepupal (3°L/PP) ovary indicates the number of ovaries with shown location of PGCs versus the total number of this class of 3°L/PP ovaries examined. Yellow cells are nascent TFs. Scale bars: in A, 20 µm for A,B; in A', 10 µm for A',B'.