PDF(Pubmed)
Abstract：
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.
摘要：
爬行动物的肤色是壮观和多样的，然而，对控制其建立的个体发育过程和决定其的分子信号通路知之甚少。这里,我们专注于豹纹壁虎幼体的带状模式的发展以及成虫向黑点的过渡。根据我们的组织学分析，我们表明，虹彩存在于孵化的白色和黄色条带中，并逐渐在成年皮肤中灭亡。此外，我们证明，在没有其他色团的情况下，黑素细胞可以在MackSuperSnow（MSS）豹纹壁虎的尾巴和背侧皮肤上自主形成斑点。这种颜色形态的特征是幼体中均匀的黑色着色和成年期的黑点;我们确定他们的皮肤在两个阶段都没有黄花和虹膜。我们的遗传分析确定了MSS壁虎的PAX7转录因子中的13个核苷酸缺失，影响其蛋白质编码序列。通过我们对胚胎皮肤的单细胞转录组学分析，我们证实PAX7在虹膜和黄花虫中表达，这表明它在两种染色体的分化中起着关键作用。我们在整装胚胎上的原位杂交记录了皮肤图案形成的动态以及它在PAX7突变体中的影响。我们假设黑色素细胞-虹膜细胞的相互作用会导致孵化的带状模式，黑斑的形成是胚胎后皮肤中黑色素细胞的固有能力。
