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The Caenorhabditis elegans p120 catenin homologue, JAC-1, modulates cadherin-catenin function during epidermal morphogenesis.

Pettitt J, Cox EA, Broadbent ID, Flett A, Hardin J - J. Cell Biol. (2003)

Bottom Line: We have examined the role of the single Caenorhabditis elegans p120ctn homologue JAC-1 (juxtamembrane domain [JMD]-associated catenin) during epidermal morphogenesis.Surprisingly, depleting JAC-1 expression using RNA interference (RNAi) does not result in any obvious defects in embryonic or postembryonic development.However, jac-1(RNAi) does increase the severity and penetrance of morphogenetic defects caused by a hypomorphic mutation in the hmp-1/alpha-catenin gene.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cell Biology, University of Aberdeen Institute of Medical Sciences, Aberdeen AB25 2ZD, Scotland, UK. j.pettitt@abdn.ac.uk

ABSTRACT
The cadherin-catenin complex is essential for tissue morphogenesis during animal development. In cultured mammalian cells, p120 catenin (p120ctn) is an important regulator of cadherin-catenin complex function. However, information on the role of p120ctn family members in cadherin-dependent events in vivo is limited. We have examined the role of the single Caenorhabditis elegans p120ctn homologue JAC-1 (juxtamembrane domain [JMD]-associated catenin) during epidermal morphogenesis. Similar to other p120ctn family members, JAC-1 binds the JMD of the classical cadherin HMR-1, and GFP-tagged JAC-1 localizes to adherens junctions in an HMR-1-dependent manner. Surprisingly, depleting JAC-1 expression using RNA interference (RNAi) does not result in any obvious defects in embryonic or postembryonic development. However, jac-1(RNAi) does increase the severity and penetrance of morphogenetic defects caused by a hypomorphic mutation in the hmp-1/alpha-catenin gene. In these hmp-1 mutants, jac-1 depletion causes failure of the embryo to elongate into a worm-like shape, a process that involves contraction of the epidermis. Associated with failed elongation is the detachment of actin bundles from epidermal adherens junctions and failure to maintain cadherin in adherens junctions. These results suggest that JAC-1 acts as a positive modulator of cadherin function in C. elegans.

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jac-1 encodes a C. elegans p120ctn homologue that interacts specifically with the JMD of HMR-1. (A) Structure of the jac-1 gene. Exons are represented by shaded boxes; two putative alternative exons are lightly shaded. The spliced-leader sequences found at the start of each alternative jac-1 transcript are indicated. (B) Schematic structure of JAC-1 compared with Dp120ctn and human δ-catenin (GenBank/EMBL/DDBJ accession nos. AAF33245 and Q9UQB3, respectively). Fn3 domains and Arm repeats are represented as open and shaded boxes, respectively. Interruptions in Arm repeats 4, 6, and 9 are indicated by unshaded regions. The numbers indicate the percent amino acid identity shared between corresponding Arm repeats. Predicted alternative start codons for JAC-1 are indicated by vertical lines. (C) ClustalW alignment of the Arm repeat regions (as defined by Anastasiadis and Reynolds, 2000) of JAC-1, Dp120, and δ-catenin (beginning at amino acids 594, 201, and 527, respectively). Black countershading indicates identical residues; gray, similarity. The borders of each Arm repeat are indicated by vertical lines. (D) JAC-1 interacts specifically with the JMD of HMR-1 in the yeast two-hybrid system. Growth on minus Ura, Leu, His media containing 1 mM 3-AT indicates interaction between the activation domain fusion proteins (JAC-1 and HMP-2) and the binding domain fusion proteins (HMR-1).
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fig1: jac-1 encodes a C. elegans p120ctn homologue that interacts specifically with the JMD of HMR-1. (A) Structure of the jac-1 gene. Exons are represented by shaded boxes; two putative alternative exons are lightly shaded. The spliced-leader sequences found at the start of each alternative jac-1 transcript are indicated. (B) Schematic structure of JAC-1 compared with Dp120ctn and human δ-catenin (GenBank/EMBL/DDBJ accession nos. AAF33245 and Q9UQB3, respectively). Fn3 domains and Arm repeats are represented as open and shaded boxes, respectively. Interruptions in Arm repeats 4, 6, and 9 are indicated by unshaded regions. The numbers indicate the percent amino acid identity shared between corresponding Arm repeats. Predicted alternative start codons for JAC-1 are indicated by vertical lines. (C) ClustalW alignment of the Arm repeat regions (as defined by Anastasiadis and Reynolds, 2000) of JAC-1, Dp120, and δ-catenin (beginning at amino acids 594, 201, and 527, respectively). Black countershading indicates identical residues; gray, similarity. The borders of each Arm repeat are indicated by vertical lines. (D) JAC-1 interacts specifically with the JMD of HMR-1 in the yeast two-hybrid system. Growth on minus Ura, Leu, His media containing 1 mM 3-AT indicates interaction between the activation domain fusion proteins (JAC-1 and HMP-2) and the binding domain fusion proteins (HMR-1).

Mentions: We, and others (Natarajan et al., 2001), have identified a single predicted gene, Y105C5B.21, that is capable of encoding a p120ctn homologue (Fig. 1)Figure 1.


The Caenorhabditis elegans p120 catenin homologue, JAC-1, modulates cadherin-catenin function during epidermal morphogenesis.

Pettitt J, Cox EA, Broadbent ID, Flett A, Hardin J - J. Cell Biol. (2003)

jac-1 encodes a C. elegans p120ctn homologue that interacts specifically with the JMD of HMR-1. (A) Structure of the jac-1 gene. Exons are represented by shaded boxes; two putative alternative exons are lightly shaded. The spliced-leader sequences found at the start of each alternative jac-1 transcript are indicated. (B) Schematic structure of JAC-1 compared with Dp120ctn and human δ-catenin (GenBank/EMBL/DDBJ accession nos. AAF33245 and Q9UQB3, respectively). Fn3 domains and Arm repeats are represented as open and shaded boxes, respectively. Interruptions in Arm repeats 4, 6, and 9 are indicated by unshaded regions. The numbers indicate the percent amino acid identity shared between corresponding Arm repeats. Predicted alternative start codons for JAC-1 are indicated by vertical lines. (C) ClustalW alignment of the Arm repeat regions (as defined by Anastasiadis and Reynolds, 2000) of JAC-1, Dp120, and δ-catenin (beginning at amino acids 594, 201, and 527, respectively). Black countershading indicates identical residues; gray, similarity. The borders of each Arm repeat are indicated by vertical lines. (D) JAC-1 interacts specifically with the JMD of HMR-1 in the yeast two-hybrid system. Growth on minus Ura, Leu, His media containing 1 mM 3-AT indicates interaction between the activation domain fusion proteins (JAC-1 and HMP-2) and the binding domain fusion proteins (HMR-1).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2172718&req=5

fig1: jac-1 encodes a C. elegans p120ctn homologue that interacts specifically with the JMD of HMR-1. (A) Structure of the jac-1 gene. Exons are represented by shaded boxes; two putative alternative exons are lightly shaded. The spliced-leader sequences found at the start of each alternative jac-1 transcript are indicated. (B) Schematic structure of JAC-1 compared with Dp120ctn and human δ-catenin (GenBank/EMBL/DDBJ accession nos. AAF33245 and Q9UQB3, respectively). Fn3 domains and Arm repeats are represented as open and shaded boxes, respectively. Interruptions in Arm repeats 4, 6, and 9 are indicated by unshaded regions. The numbers indicate the percent amino acid identity shared between corresponding Arm repeats. Predicted alternative start codons for JAC-1 are indicated by vertical lines. (C) ClustalW alignment of the Arm repeat regions (as defined by Anastasiadis and Reynolds, 2000) of JAC-1, Dp120, and δ-catenin (beginning at amino acids 594, 201, and 527, respectively). Black countershading indicates identical residues; gray, similarity. The borders of each Arm repeat are indicated by vertical lines. (D) JAC-1 interacts specifically with the JMD of HMR-1 in the yeast two-hybrid system. Growth on minus Ura, Leu, His media containing 1 mM 3-AT indicates interaction between the activation domain fusion proteins (JAC-1 and HMP-2) and the binding domain fusion proteins (HMR-1).
Mentions: We, and others (Natarajan et al., 2001), have identified a single predicted gene, Y105C5B.21, that is capable of encoding a p120ctn homologue (Fig. 1)Figure 1.

Bottom Line: We have examined the role of the single Caenorhabditis elegans p120ctn homologue JAC-1 (juxtamembrane domain [JMD]-associated catenin) during epidermal morphogenesis.Surprisingly, depleting JAC-1 expression using RNA interference (RNAi) does not result in any obvious defects in embryonic or postembryonic development.However, jac-1(RNAi) does increase the severity and penetrance of morphogenetic defects caused by a hypomorphic mutation in the hmp-1/alpha-catenin gene.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cell Biology, University of Aberdeen Institute of Medical Sciences, Aberdeen AB25 2ZD, Scotland, UK. j.pettitt@abdn.ac.uk

ABSTRACT
The cadherin-catenin complex is essential for tissue morphogenesis during animal development. In cultured mammalian cells, p120 catenin (p120ctn) is an important regulator of cadherin-catenin complex function. However, information on the role of p120ctn family members in cadherin-dependent events in vivo is limited. We have examined the role of the single Caenorhabditis elegans p120ctn homologue JAC-1 (juxtamembrane domain [JMD]-associated catenin) during epidermal morphogenesis. Similar to other p120ctn family members, JAC-1 binds the JMD of the classical cadherin HMR-1, and GFP-tagged JAC-1 localizes to adherens junctions in an HMR-1-dependent manner. Surprisingly, depleting JAC-1 expression using RNA interference (RNAi) does not result in any obvious defects in embryonic or postembryonic development. However, jac-1(RNAi) does increase the severity and penetrance of morphogenetic defects caused by a hypomorphic mutation in the hmp-1/alpha-catenin gene. In these hmp-1 mutants, jac-1 depletion causes failure of the embryo to elongate into a worm-like shape, a process that involves contraction of the epidermis. Associated with failed elongation is the detachment of actin bundles from epidermal adherens junctions and failure to maintain cadherin in adherens junctions. These results suggest that JAC-1 acts as a positive modulator of cadherin function in C. elegans.

Show MeSH
Related in: MedlinePlus