ZOO-1
Supplemental material for the following paper:
Lockwood, C., Zaidel-Bar, and Hardin, J. (2008). The C. elegans Zonula Occludens Ortholog cooperates with the cadherin complex to recruit actin during morphogenesis. Curr. Biol.18:1333-7. PubMed
Summary
The dramatic cell shape changes necessary to form a multicellular organism require cell-cell junctions to be both pliable and strong. The Zonula Occludens (ZO) subfamily of membrane-associated guanylate kinases (MAGUKs) are scaffolding molecules thought to regulate cell-cell adhesion [1-3], but there is little known about their roles in vivo. To elucidate the functional role of ZO proteins in a living embryo, we have characterized the sole C. elegans ZO family member, ZOO-1. ZOO-1 localizes with the cadherin-catenin complex during development and its junctional recruitment requires the transmembrane proteins HMR-1/E-cadherin and VAB-9/claudin, but surprisingly, not HMP-1/α-catenin or HMP-2/β-catenin. zoo-1 knockdown results in lethality during elongation, resulting in the rupture of epidermal cell-cell junctions under stress and failure of epidermal sheet sealing at the ventral midline. Consistent with a role in recruiting actin to the junction in parallel to the cadherin-catenin complex, zoo-1 loss of function reduces the dynamic recruitment of actin to junctions and enhances the severity of actin filament defects in hypomorphic alleles of hmp-1 and hmp-2. These results show that ZOO-1 cooperates with the cadherin-catenin complex to dynamically regulate strong junctional anchorage to the actin cytoskeleton during morphogenesis.
Movie 1. ZOO-1::GFP in a wild-type embryo.
Frames were collected at 200-second time intervals for 90 minutes. Movie is displayed at a rate of 7 frames per second.
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Movie 2. Elongation in a wild-type embryo.
Frames were collected at 6-minute time intervals for 4 hours. Movie is displayed at a rate of 7 frames per second.
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Movie 3. Elongation in an rrf-3(pk1426) embryo.
Frames were collected at 6-minute time intervals for 4 hours. Movie is displayed at a rate of 7 frames per second.
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Movie 4. An elongation rupture phenotype in a zoo-1(RNAi);rrf-3(pk1426) embryo.
Frames were collected at 6-minute time intervals for 3 hours. Movie is displayed at a rate of 7 frames per second.
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Movie 5. F-actin dynamics during ventral enclosure in a wild-type embryo expressing vab-10::ABD::GFP.
The boxed regions show extensive actin accumulation between two pairs of ventral epidermal cells (ABpr/laappap and ABpr/laappp). The pair between these two pairs (ABpr/laapppa) immediately fuses in wild-type embryos to form a syncytium. Frames were collected at 60-second time intervals. Elapsed time in seconds is shown.
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Movie 6. F-actin dynamics in a zoo-1(RNAi);rrf-3(pk1426) embryo expressing vab-10::ABD::GFP.
The asterisk show a region in which ventral midline defects occur. The boxed region shows ABpr/laappp, which have failed to make contact at the midline. Frames were collected at 60-second time intervals. Elapsed time in seconds is shown.
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Movie 7. F-actin dynamics in a zoo-1(RNAi);rrf-3(pk1426) embryo expressing vab-10::ABD::GFP.
The boxed region shows ABpr/laapppa, which have failed to make contact at the midline, and hence have not fused. Frames were collected at 60-second time intervals. Elapsed time in seconds is shown.
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Movie 8. An elongation arrest phenotype in a hmp-1(fe4) embryo.
Frames were collected at 6-minute time intervals for 4 hours. Movie is displayed at a rate of 7 frames per second.
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Movie 9. A Humpback phenotype in a zoo-1(RNAi);hmp-1(fe4) embryo.
Frames were collected at 6-minute time intervals for 4 hours. Movie is displayed at a rate of 7 frames per second.
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Movie 10. An elongation rupture phenotype in a zoo-1(RNAi);hmp-(fe4) embryo.
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