Figure 5. Zona pellucida domain containing proteins (ZP) characterization.

(A) Lobster ZP domain phylogenetic tree show distinct clustering of the eight transcripts that show differential expression throughout metamorphosis (boxed) from those who don’t. (B) ZP transcripts with differential expression all show same trend; no expression in inter-molt phyllosoma prior to metamorphosis (stage 1), followed by a sharp incline in phyllosoma at the start of the metamorphic molt (20% gut retraction; stage 2), a decline in late stage metamorphosing phyllosoma (80% gut retraction; stage 3), with no expression in post-metamorphosis pueruli (stage 4) and H-pahse pueruli (stage 5). (C) The architecture of the two most prominently expressed during metamorphosis is similar to the Drosophila ‘dusky’, ‘dusky-like’ and ‘miniature’, all associated with wing morphogenesis and defining the apical cell shape during formation of the cuticle⁶⁷. The putative protein starts with a short signal peptide (SP), followed by the ZP domain, a conserved RxxR motif which might enable post-translational cleavage of the protein and a transmembrane domain (TM) at the C’. (D) Radial phylogram of the lobster ZP domains with ZP domains of various ‘dusky’, ‘dusky-like’ and ‘cucticlin-1’ from insects localize the two most prominently expressed transcripts with the insects (see magnification in Fig. 5D’ and D”; please refer to Table S1 for list of proteins used in the tree). Bar represents amino acid substitutions per site.