Project description:Various species of teleost fish, amphibians, and neonatal mammals can regenerate their hearts following injury. Certain processes, including extracellular matrix remodelling, a switch from oxidative to glycolytic metabolism and sarcomere disorganization are believed to be critical to heart regeneration. However, whether all regenerating species follow the same pathway to regeneration is not known. Here, we use mass-spectrometry based proteomics to characterize the cellular processes that occur in the heart of a reptile, the leopard gecko (Eublepharis macularius) following injury. The hearts were damaged using a cryoprobe and wound sites were sampled at 3-, 14-, 30- and 100-days post injury (dpi). The proteomes of these were compared to those from sham operated geckos. Overall, 1116 proteins were identified in the wound sites and 579 were differentially expressed across at least two time points. This includes an increase in agrin at 14-dpi, a protein thought to be required for cardiomyocyte proliferation and heart regeneration. Interaction network analysis indicates that there is enrichment of Gene Ontology (GO) terms related to transcription and translation by 14-dpi, but a concurrent decrease in GO terms related to oxidative and glycolytic metabolism, and sarcomere organization. Importantly, GO terms related to the structure and function of mitochondria as well as sarcomere organization were enriched at 100-dpi compared to 3-dpi, and 14-dpi. There were no GO terms identified as differing between sham and 100 dpi hearts, suggesting full regeneration. This work indicates that the gecko heart can regenerate and that this involves reorganization of cellular pathways associated with mitosis, energy production and contractile function.
Project description:BackgroundGeckos are among the most species-rich reptile groups and the sister clade to all other lizards and snakes. Geckos possess a suite of distinctive characteristics, including adhesive digits, nocturnal activity, hard, calcareous eggshells, and a lack of eyelids. However, one gecko clade, the Eublepharidae, appears to be the exception to most of these 'rules' and lacks adhesive toe pads, has eyelids, and lays eggs with soft, leathery eggshells. These differences make eublepharids an important component of any investigation into the underlying genomic innovations contributing to the distinctive phenotypes in 'typical' geckos.FindingsWe report high-depth genome sequencing, assembly, and annotation for a male leopard gecko, Eublepharis macularius (Eublepharidae). Illumina sequence data were generated from seven insert libraries (ranging from 170 to 20 kb), representing a raw sequencing depth of 136X from 303 Gb of data, reduced to 84X and 187 Gb after filtering. The assembled genome of 2.02 Gb was close to the 2.23 Gb estimated by k-mer analysis. Scaffold and contig N50 sizes of 664 and 20 kb, respectively, were comparable to the previously published Gekko japonicus genome. Repetitive elements accounted for 42 % of the genome. Gene annotation yielded 24,755 protein-coding genes, of which 93 % were functionally annotated. CEGMA and BUSCO assessment showed that our assembly captured 91 % (225 of 248) of the core eukaryotic genes, and 76 % of vertebrate universal single-copy orthologs.ConclusionsAssembly of the leopard gecko genome provides a valuable resource for future comparative genomic studies of geckos and other squamate reptiles.