RSPO2 inhibition of RNF43 and ZNRF3 governs limb development independently of LGR4/5/6

Four R-spondin secreted ligands (RSPO1-RSPO4) act through their LGR4, LGR5 and LGR6 receptors amplifying WNT signalling. An allelic series of recessive RSPO2 mutations in humans causes tetra-amelia syndrome, characterized by lung aplasia and a total absence of the four limbs. Szenker-Ravi et al. published in Nature that RSPO2, without the LGR4/5/6 receptors, serves as a direct antagonistic ligand to RNF43 and ZNRF3, constituting a master switch that governs limb specification.

Photo credit: Amelie Fossul

Gene expression during Xenopus embryogenesis measured at single-cell resolution

Briggs et al. performed single-cell RNA sequencing at 10 embryonic stages 5 to 22 hours post fertilization. Gene activity data read from the mRNA of 137,000 cells show that while the frog embryo appears to be in an undifferentiated state, cells begin to take on their eventual identities. Their findings are published in Science.

Quantitative Proteomics After Spinal Cord Injury

Lee-Liu et al. published in Molecular & Cellular Proteomics their study measuring the proteomic response in X. laevis after spinal cord injury (SCI).

SCI was induced at regerative and non-regenerative stages. They quantified a total of 6,384 proteins, with 172 showing significant differential expression in the regenerative stage and 240 in the nonregenerative stage, with an overlap of only 14 proteins.

Morpholino Side Effects

Gentsch et al. published in Developmental Cell highlight:

Brachyury KO and KD in frog equally affect phenotype-causing downstream genes.
Other transcriptional anomalies are unique to morpholino-based KDs and controls.
Morpholinos can trigger an innate immune response and off-target mis-splicing.
Optimization of KD conditions mitigates but does not eliminate these side effects.

Tissue stiffening coordinates morphogenesis by triggering collective cell migration in vivo

Neural crest cells sense the stiffening in the extracellular matrix of the underlying mesoderm through integrin signalling, and undergo an epithelial-to-mesenchymal transition before starting their collective migration. Barriga et al published in Nature.

17th International Xenopus Conference

Save the date!

August 12-16, 2018.

Seattle, Washington, USA.

Early Registration: June 29, 2018.

Click here to go to the meeting website.

Society for Developmental Biology 77th Annual Meeting

Portland, OR USA

July 20-24, 2018

Registration now open.

Visit: https://www.sdbonline.org/2018mtg

9th Aquatic Models of Human Disease Conference

September 29 – October 4, 2018

Marine Biological Laboratory

Woods Hole, MA USA

RSPO2 inhibition of RNF43 and ZNRF3 governs limb development independently of LGR4/5/6

Four R-spondin secreted ligands (RSPO1-RSPO4) act through their LGR4, LGR5 and LGR6 receptors amplifying WNT signalling. An allelic series of recessive RSPO2 mutations in humans causes tetra-amelia syndrome, characterized by lung aplasia and a total absence of the four limbs. Szenker-Ravi et al. published in Nature that RSPO2, without the LGR4/5/6 receptors, serves as a direct antagonistic ligand to RNF43 and ZNRF3, constituting a master switch that governs limb specification.

Photo credit: Amelie Fossul