Figure 6. Correlation between
aff-1 Expression and Its Fusogenic Effect. (A-F) Nomarski (left)
aff-1 promoter GFP fusion (
aff-1p::GFP) fluorescence signal (center) and overlaid (right) images.(A) At mid-L3,
aff-1 is expressed specifically in the AC (arrowhead).(B) AC expression is retained while the vulva invaginates during early L4.(C) Expression of the
aff-1 transcriptional reporter is induced in the vulval D ring cells (arrows) and in the AC-utse syncytium as it is formed in late L4 stage (arrowhead).(D) A different focal plane from the same worm shown in (C) where the AC-utse expression is highlighted (arrows).(E) The vulD expression of
aff-1 is retained in adult worms (arrows).(F) In
lin29(n482) mutants, AC and utse fusion do not occur (Newman et al., 2000). A single AC (arrowhead) is localized adjacent to a single utse cell (arrow).
aff-1 signal in utse cells that did not fuse with the AC cell demonstrates that
aff-1 is autonomously expressed in the utse cells.(G) Confocal projection of
aff-1 expression pattern in L4 larva (dorsolateral view).
aff-1 is expressed in VulD ring, the utse, and in the seams. Seam cell expression starts at mid-L4 just before
aff-1-dependent fusion.(H) Confocal projection of the H-shaped utse syncytium where
aff-1 is expressed (ventral view). In addition,
aff-1 expression is detected in two rows of lateral seam cells and in the two uterine
ut4 toroids (Ut4).(I) Subcellular localization of AFF-1::GFP protein in the AC during invasion (lateral view of confocal image). The fusion protein was specifically expressed in the AC by the anchor-cell-specific promoter pAC (Kirouac and Sternberg, 2003). AFF-1::GFP protein is localized in intracellular compartments and at the plasma membrane (arrowheads).(J) Similar subcellular localization of AFF-1::GFP was detected at the time of AC fusion in a confocal image (lateral view).(A-F) Scale bar 5 um; (G) 10 um; (H) 20 um.