Dataset Information

Solution Structure of C. elegans UNC-6: A Nematode Paralogue of the Axon Guidance Protein Netrin-1.

ABSTRACT: UNCoordinated-6 (UNC-6) was the first member of the netrin family to be discovered in Caenorhabditis elegans. With homology to human netrin-1, it is a key signaling molecule involved in directing axon migration in nematodes. Similar to netrin-1, UNC-6 interacts with multiple receptors (UNC-5 and UNC-40, specifically) to guide axon migration in development. As a result of the distinct evolutionary path of UNC-6 compared to vertebrate netrins, we decided to employ an integrated approach to study its solution behavior and compare it to the high-resolution structure we previously published on vertebrate netrins. Dynamic light scattering and analytical ultracentrifugation on UNC-6 (with and without its C-domain) solubilized in a low-ionic strength buffer suggested that UNC-6 forms high-order oligomers. An increase in the buffer ionic strength resulted in a more homogeneous preparation of UNC-6, that was used for subsequent solution x-ray scattering experiments. Our biophysical analysis of UNC-6 ΔC solubilized in a high-ionic strength buffer suggested that it maintains a similar head-to-stalk arrangement as netrins -1 and -4. This phenomenon is thought to play a role in the signaling behavior of UNC-6 and its ability to move throughout the extracellular matrix.

SUBMITTER: Krahn N

PROVIDER: S-EPMC6554493 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Solution Structure of C. elegans UNC-6: A Nematode Paralogue of the Axon Guidance Protein Netrin-1.

Krahn Natalie N Meier Markus M Reuten Raphael R Koch Manuel M Stetefeld Joerg J Patel Trushar R TR

Biophysical journal 20190503 11

UNCoordinated-6 (UNC-6) was the first member of the netrin family to be discovered in Caenorhabditis elegans. With homology to human netrin-1, it is a key signaling molecule involved in directing axon migration in nematodes. Similar to netrin-1, UNC-6 interacts with multiple receptors (UNC-5 and UNC-40, specifically) to guide axon migration in development. As a result of the distinct evolutionary path of UNC-6 compared to vertebrate netrins, we decided to employ an integrated approach to study i ...[more]

PMID: 31103237

Similar Datasets

Project description:Recent studies in vertebrates and Caenorhabditis elegans have reshaped models of how the axon guidance cue UNC-6/Netrin functions in dorsal-ventral axon guidance, which was traditionally thought to form a ventral-to-dorsal concentration gradient that was actively sensed by growing axons. In the vertebrate spinal cord, floorplate Netrin1 was shown to be largely dispensable for ventral commissural growth. Rather, short range interactions with Netrin1 on the ventricular zone radial glial stem cells was shown to guide ventral commissural axon growth. In C. elegans, analysis of dorsally-migrating growth cones during outgrowth has shown that growth cone polarity of filopodial extension is separable from the extent of growth cone protrusion. Growth cones are first polarized by UNC-6/Netrin, and subsequent regulation of protrusion by UNC-6/Netrin is based on this earlier-established polarity (the Polarity/Protrusion model). In both cases, short-range or even haptotactic mechanisms are invoked: in vertebrate spinal cord, interactions of growth cones with radial glia expressing Netrin-1; and in C. elegans, a potential close-range interaction that polarizes the growth cone. To explore potential short-range and long-range functions of UNC-6/Netrin, a potentially membrane-anchored transmembrane UNC-6 (UNC-6(TM)) was generated by genome editing. unc-6(tm) was hypomorphic for dorsal VD/DD axon pathfinding, indicating that it retained some unc-6 function. Polarity of VD growth cone filopodial protrusion was initially established in unc-6(tm), but was lost as the growth cones migrated away from the unc-6(tm) source in the ventral nerve cord. In contrast, ventral guidance of the AVM and PVM axons was equally severe in unc-6(tm) and unc-6(null). Together, these results suggest that unc-6(tm) retains short-range functions but lacks long-range functions due to reduced secreted UNC-6. Ectopic unc-6(+) expression from non-ventral sources did not dramatically perturb dorsal VD growth cone polarity or axon outgrowth, suggesting that ectopic UNC-6 cannot redirect polarity once it is established in the VD/DD neurons. This is not what would be expected of a growth cone dynamically reading a gradient of UNC-6, but is consistent with the Polarity/protrusion model of growth cone guidance away from UNC-6/Netrin.

Dataset Information

Solution Structure of C. elegans UNC-6: A Nematode Paralogue of the Axon Guidance Protein Netrin-1.

Publications

Solution Structure of C. elegans UNC-6: A Nematode Paralogue of the Axon Guidance Protein Netrin-1.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets