Ultrastructure of the epidermis in <i>y</i>^<i>2</i>, <i>cho</i>^<i>2</i>, <i>v</i> and the <i>tyn</i>^<i>1</i> mutant.

TEM images of epidermis in stage 17 embryos. (A) Three cuticle layers formed on the plasma membrane of epidermal cells (PM, arrowhead): the outermost envelope (Env), intermediate epicuticle (Epi), and innermost procuticle (Pro). (B) The surface of the envelope layer of the tyn1 mutant was disorganized (arrow). (A’), (B’): Enlarged views of the region indicated by a rectangle in (A) and (B), respectively. In control samples, the five sublayers constituting the envelope were observed clearly, as alternating electron-dense and lucid layers in (C). (D) In the tyn1 mutant, one or two surface sublayers were broken in many regions (arrowheads), causing a rough surface with extensive debris (arrows). Scale bar: 200 nm for (A), (B) and 50 nm for (A’), (B)’, (C), (D).