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Full-Text Articles in Microbiology
Runx2 Is Essential For Larval Hyobranchial Cartilage Formation In Xenopus Laevis, Ryan Kerney, Joshua Gross, James Hanken
Runx2 Is Essential For Larval Hyobranchial Cartilage Formation In Xenopus Laevis, Ryan Kerney, Joshua Gross, James Hanken
Ryan Kerney
The vertebrate transcription factor protein Runx2 is regarded as a “master regulator” of bone formation due to the dramatic loss of the osseous skeleton in the mouse homozygous knockout. However, Runx2 mRNA also is expressed in the pre-hypertrophic cartilaginous skeleton of the mouse and chicken, where its developmental function is largely unknown. Several tiers of Runx2 regulation exist in the mouse, any of which may account for its seeming biological inactivity during early stages of skeletogenesis. Unlike mouse and chicken, zebrafish require Runx2 function in early cartilage differentiation. The present study reveals that the earlier functional role of Runx2 in …
Cranial Ontogeny In Philautus Silus (Anura: Ranidae: Rhacophorinae) Reveals Few Similarities With Other Direct-Developing Anurans, Ryan Kerney, Madhava Meegaskumbura, Kelum Manamendra-Arachchi, James Hanken
Cranial Ontogeny In Philautus Silus (Anura: Ranidae: Rhacophorinae) Reveals Few Similarities With Other Direct-Developing Anurans, Ryan Kerney, Madhava Meegaskumbura, Kelum Manamendra-Arachchi, James Hanken
Ryan Kerney
Direct development has evolved in rhaco- phorine frogs independently from other anuran lineages, thereby offering an opportunity to assess features associ- ated with this derived life history. Using a developmen- tal series of the direct-developing Philautus silus (Ranidae: Rhacophorinae) from Sri Lanka, we examine features of cranial morphology that are part of a suite of adaptations that facilitate feeding in free-living tadpoles, but have been changed or lost in other direct-developing lineages. Larval-specific upper jaw cartilages, which are absent from many non-rhacophorine direct-developing species (such as Eleutherodactylus coqui), develop in embryos of P. silus. Similarly, lower jaw cartilages ini- tially …