Project description:Expression data from LEOPARD Syndrome-iPS clones, BJ-iPS cells and parental Fibroblasts 9 samples in total are analyzed. Among 22011 genes in expression data, there are 3657 genes with at least 2 fold expression change between the average of the three fibroblast lines versus all of the iPS lines/HES samples. A heatmap can be generated for the expression levels for the 3657 genes and 9 samples.
Project description:The dentition of elasmobranchs (sharks, skates and rays) is uniquely productive, capable of both rapid and continuous, lifelong regeneration. Elasmobranchs represent an important group of vertebrates with a deep evolutionary history, possessing several ancient and basal characters, i.e., the continuously regenerative dentition from a specialized dental lamina. The dental lamina is an expanded component of the oral epithelia that is responsible for initiating and producing new teeth among all toothed-vertebrates. In sharks, this dynamic epithelial unit is permanent and continuous – meaning it extends to cover the entirety of each jaw (jaw-wide) and develops early during embryogenesis and retained to produce teeth for the life of the shark. It is rare for a truly embryonic vertebrate tissue to be retained for its original function for the life of the organism. The dental lamina in sharks is unique and houses teeth in a developmental series from the deepest part, where teeth are initiated, through stages of tooth development in the form of a related, family of teeth to eruption and functionality of the advanced teeth at the jaw margin. How teeth are made and regenerated is an important question in vertebrate biology; here we investigated this question in the small spotted catshark (Scyliorhinus canicula), a new model in the field of developmental biology. Specifically, we divided the shark dental lamina into stage-compartments as follows: (i) the initiation site – the successional lamina (SL); (ii) the early developing teeth (ET); (iii) the late stage developing teeth (LT); (iv) the tooth-taste junction between the superficial oral and dental epithelium at the jaw margin that separates the taste territory and the dental lamina proper (TTJ); and basi-hyal oral epithelium that is strictly non-dental and only contains taste buds (BHTB). These 5 compartments each house both a shared and unique signature of gene transcripts. This study aims to understand the transcriptomic basis of continuous tooth regeneration in the shark. In this study we combine X-ray computed tomography, classic histology, insitu hybridization, immunohistochemistry, and functional assays of novel markers, and de novo and genome guided transcriptome assemblies for each of these 5 dental lamina compartments of the hatchling (stage 34) catshark (S. canicula).
Project description:Reptilian skin coloration is spectacular and diverse, yet little is known about the ontogenetic processes that govern its establishment and the molecular signaling pathways that determine it. Here, we focus on the development of the banded pattern of leopard gecko hatchlings and the transition to black spots in the adult. With our histological analyses, we show that iridophores are present in the white and yellow bands of the hatchling and they gradually perish in the adult skin. Furthermore, we demonstrate that melanophores can autonomously form spots in the absence of the other chromatophores both on the regenerated skin of the tail and on the dorsal skin of the Mack Super Snow (MSS) leopard geckos. This color morph is characterized by uniform black coloration in hatchlings and black spots in adulthood; we establish that their skin is devoid of xanthophores and iridophores at both stages. Our genetic analyses identified a 13-nucleotide deletion in the PAX7 transcription factor of MSS geckos, affecting its protein coding sequence. With our single-cell transcriptomics analysis of embryonic skin, we confirm that PAX7 is expressed in iridophores and xanthophores, suggesting that it plays a key role in the differentiation of both chromatophores. Our in situ hybridizations on whole-mount embryos document the dynamics of the skin pattern formation and how it is impacted in the PAX7 mutants. We hypothesize that the melanophores–iridophores interactions give rise to the banded pattern of the hatchlings and black spot formation is an intrinsic capacity of melanophores in the postembryonic skin.
Project description:Among mammals, injury to the heart typically results in scar formation and diminished cardiovascular function. In contrast, some teleost fish and salamanders can replace damaged heart tissue and restore overall function. For most species, however, less is known. Here, we investigate cardiac self-repair in an amniote capable of multi-tissue regeneration, the leopard gecko (Eublepharis macularius). To create a heart lesion, we placed a liquid nitrogen-cooled metal probe directly onto the ventricle. The result was a cryoinjury to ~20% of the ventricle. Cardiac cryoinjury induced localized cardiac cell death, followed by an increase in cell proliferation by injury-adjacent cardiomyocytes and non-cardiomyocytes. By 100 days, the histology of the ventricular myocardium was near-completely restored. Echocardiography and invasive hemodynamic monitoring demonstrated that global cardiac function is restored within this timeframe, verifying functional replacement of the myocardium. To explore the molecular basis, we performed bulk RNA sequencing of the injury-adjacent tissue and found that many of the molecular mechanisms common to other cardiac regenerating species, including genes involved in heart development, glycolysis, and extracellular matrix deposition, are also conserved in geckos. Taken together, this work expands the comparative framework of heart regeneration to include reptiles and indicates that the ability to replace missing or damaged cardiomyocytes is shared across more than 350 million years of evolution.