Hannah L. Craig et al. (2006) European Worm Meeting "Understanding the Role of a Non-Peptidase Member of the ACE Family in Nematode Moulting"

R.Elwyn Isaac, Hannah L. Craig, Clare Hunton, Darren R. Brooks

[European Worm Meeting, 2006]

Hannah L. Craig1, Clare Hunton1, Darren R. Brooks2, R.Elwyn Isaac1 Analysis of the large number of protease-like genes present in animal genomes has shown that a considerable proportion of these genes code for proteins that are structurally related to peptidases, but lack key catalytic residues. These proteins are classified as non-peptidase family members. One such protein is the single member of the angiotensin-converting enzyme (ACE) family of zinc metallopeptidases found in C. elegans. ACN-1 (ACE-like non-metallopeptidase) shares considerable identity with ACE from other organisms, but lacks the conserved active site residues required for proteolytic activity. ACN-1 also differs from other ACEs in having a proline/glutamic acid-rich domain, and, towards the C-terminus, a cysteine-rich region, a proline and threonine/serine rich region and a potential GPI anchor attachment site. It has recently become apparent that an alternatively-spliced form of acn-1 may be expressed at low levels. A single EST with 5 and 3 sequence identical to acn-1, but missing a major portion of the central ACE-like domain, has been identified. Sequences showing considerable similarity to acn-1 are also present in EST and genomic datasets from several parasitic nematodes.. ACN-1 has an essential role in C. elegans development and morphogenesis. GFP-tagged ACN-1 expression was observed in the hypodermal cells and developing vulva of hermaphrodites and also the ray papillae of the male tail. Deletion of a 692 bp fragment (strain tm844, provided by Shohei Mitani, Tokyo Womens Medical College) comprising part of exon 7 and all of exons 8 and 9 resulted in arrested embryonic development and acn-1 RNAi resulted in larval arrest due to a moulting defect. Further examination showed that acn-1 RNAi-treated adults had disrupted alae, an incomplete seam syncytium and a protruding vulva. SEM images of arrested larvae showed a failure to shed the old cuticle after RNAi. Adult males displayed similar hypodermal defects, including a severely disrupted tail. The nuclear hormone receptors nhr-23 and nhr-25 were shown by RNAi to regulate expression of acn-1::gfp, hence positioning acn-1 downstream of these nuclear hormone receptors in the genetic cascade controlling moulting.

Hannah L Craig et al. (2005) International Worm Meeting "Understanding the role of a novel ACE family member in nematode moulting."

Clare Hunton, Darren R Brooks, R Elwyn Isaac, Hannah L Craig

[International Worm Meeting, 2005]

Analysis of the large number of protease-like genes present in animal genomes has shown that a considerable proportion of these genes code for proteins that are structurally related to peptidases, but lack key catalytic residues. These proteins are classified as non-peptidase family members. One such protein is the single member of the angiotensin-converting enzyme (ACE) family of zinc metallopeptidases found in C. elegans. ACN-1 (ACE-like non-metallopeptidase) shares considerable identity with ACE from other organisms, but lacks the conserved active site residues required for proteolytic activity. ACN-1 also differs from other ACEs in having a proline/glutamic acid-rich domain, and, towards the C-terminus, a cysteine-rich region, a proline and threonine/serine rich region and a potential GPI anchor attachment site. It has recently become apparent that an alternatively-spliced form of acn-1 may be expressed at low levels. A single EST with 5 and 3 sequence identical to acn-1, but missing a major portion of the central ACE-like domain, has been identified. Sequences showing considerable similarity to acn-1 are also present in EST and genomic datasets from several parasitic nematodes.ACN-1 has an essential role in C. elegans development and morphogenesis. GFP-tagged ACN-1 expression was observed in the hypodermal cells and developing vulva of hermaphrodites and also the ray papillae of the male tail. Deletion of a 692 bp fragment comprising part of exon 7 and all of exons 8 and 9 resulted in arrested embryonic development and acn-1 RNAi resulted in larval arrest due to a moulting defect. Further examination showed that acn-1 RNAi-treated adults had disrupted alae, an incomplete seam syncytium and a protruding vulva. Adult males displayed similar hypodermal defects, including a severely disrupted tail. The nuclear hormone receptors nhr-23 and nhr-25 were shown by RNAi to regulate expression of acn-1::gfp, hence positioning acn-1 downstream of these nuclear hormone receptors in the genetic cascade controlling moulting.We acknowledge Shohei Mitani (Tokyo Women's Medical College) for provision of the acn-1 deletion mutant, strain tm844.