Shaidani, N.-I. | Search bioRxiv

bioRxiv2022

Age associated DNA methylation changes in Xenopus frogs

Age-associated changes in DNA methylation have been widely established and characterized in mammals but not yet extended to other species. We present clear evidence that the aquatic vertebrate species Xenopus tropicalis displays clear patterns of age-associated changes in DNA methylation. This observation allows us to leverage the unique resources available for Xenopus to study how DNA methylation relates to other hallmarks of aging. We have generated whole genome bisulfite sequencing (WGBS) profiles in nine samples representing young, mature and old adults and characterize the gene- and chromosome-scale changes. Moreover, we selected a few thousands CpG sites to expand the findings in a larger cohort of individuals through targeted DNA methylation analysis to produce a cost effective epigenetic clock assay.

systems biology↗

bioRxiv2021

Generation of a new six1-null line in Xenopus tropicalis for study of development and congenital disease

The vertebrate Six (Sine oculis homeobox) family of homeodomain transcription factors play critical roles in the development of several organs. Six1 plays a central role in cranial placode development, including the precursor tissues of the inner ear, as well as other cranial sensory organs and the kidney. In humans, mutations in SIX1 underlie some cases of branchio-oto-renal syndrome (BOR), which is characterized by moderate to severe hearing loss. We utilized CRISPR/Cas9 technology to establish a six1 mutant line in Xenopus tropicalis that is available to the research community. We demonstrate that at larval stages, the six1-null animals show severe disruptions in gene expression of putative Six1 target genes in the otic vesicle, cranial ganglia, branchial arch and neural tube. At tadpole stages, six1-null animals display dysmorphic Meckels, ceratohyal and otic capsule cartilage morphology. This mutant line will be of value for the study of the development of several organs as well as congenital syndromes that involve these tissues.

developmental biology↗