Evolutionarily conserved Tbx5-Wnt2/2b pathway orchestrates cardiopulmonary development

Steimle et al. published in PNAS the evolutionary conservation of tbx5-wnt2/2b driving a bidirectional signaling loop between cardiopulmonary mesoderm and the foregut endoderm. This specifies endodermal pulmonary specification and mesodermal cardiac atrial septation.

2nd European Amphibian Conference

Second European Amphibian Club conference to be held 26th-29th June 2019, in Lutherstadt-Wittenberg, Germany.
Abstract deadline: April 15, 2019.

Xenopus animal cap transcriptome

Building a mucociliary epithelium.

Angerilli et al.published in Nucleic Acids Research the dynamic transcriptional landscape in X. tropicalis Animal Cap explants during differentiation into mucociliary epithelium.

Providing an online Web Tool, they detail global changes in mRNA expression, an unanticipated diversity of mRNA splicing isoforms, expression of repetitive DNA elements, and the complexity of circular RNAs.

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.

Evolutionarily conserved Tbx5-Wnt2/2b pathway orchestrates cardiopulmonary development

Steimle et al. published in PNAS the evolutionary conservation of tbx5-wnt2/2b driving a bidirectional signaling loop between cardiopulmonary mesoderm and the foregut endoderm. This specifies endodermal pulmonary specification and mesodermal cardiac atrial septation.