Figure 2. Mutations in hNF2 alter the subcellular localization of the Merlin protein expressed in Drosophila.

Confocal optical sections of wing imaginal epithelia, either cutting deeply into the epithelium (‘Cross section’) or tangentially through the apical surface of the epithelium, are presented for each allele or isoform. A–B) NF2 isoform 1 is primarily localized to the apical membrane (arrows) of these polarized epithelial cells, and adopts a punctate appearance at the apical cortex that is not clearly associated with cell boundaries (see inset at right). In addition, some punctate staining is observed basally (arrowheads in A). C–D) In contrast isoform 2, while still primarily apical (arrows, C), appears associated with cell boundaries (outlining the periphery of the apical ends of cells in D) and does not form punctae. The localizations of the K413E (E–F) and L64P (G–H) point mutations appear similar to that of isoform 1. The Δ2-3 deletion allele (I-J) appears localized to the lateral cell cortex, somewhat similar to isoform 2, but less strongly apically localized (arrows mark apical; also note staining throughout the basolateral domain in I). NF2^1-356 (K–L) is substantially cytoplasmic and fails to accumulate apically while NF2^351-595 (M–N) shows some apical enhancement (arrows in M). Both truncations display substantial cytoplasmic localizations, as indicated by the tangential views (compare L and N to J).