Grone Brian P, Butler Julie M, Wayne Christy R, Maruska Karen P
Gladstone Institutes, San Francisco, California, USA.
Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA.
J Comp Neurol. 2021 Jul 1;529(10):2596-2619. doi: 10.1002/cne.25113. Epub 2021 Feb 2.
The corticotropin-releasing hormone and urocortin family of peptides consists of five members in many vertebrates: CRH (crha/crhb in teleosts), CRH2, UCN/UTS1, UCN2, and UCN3. These genes differ in expression pattern, as well as receptor affinity, allowing them to serve a wide range of functions in a variety of species. To better understand the roles of these genes in a single species, we examined their expression patterns in the cichlid fish Astatotilapia burtoni. In situ hybridization to map mRNA expression patterns of crhb, uts1, ucn2, and ucn3 in the brain revealed conserved and distinct spatial features of expression. crhb- and uts1-expressing cells were the most broadly distributed, with several areas of co-regionalization. ucn3 was less abundant but was found in discrete regions throughout the extent of the brain, with high expression in the cerebellum, while ucn2 was restricted to only a few areas. RT-PCR showed that while crhb, uts1, and ucn3 are found in several body tissues and widespread throughout the brain, ucn2 is quite restricted in the brain, and crha is only expressed in the eye. Bayesian phylogenetic analyses identified detailed relationships and novel orthologs in the urocortin family. We found evidence for a UCN2 gene loss in some reptiles. Our detailed description of the complete family of genes in the central nervous system of a model organism will inform future studies on the function of these genes in A. burtoni and provides a foundation for comparative studies with teleosts and other vertebrates.
促肾上腺皮质激素释放激素（硬骨鱼中的crha/crhb）、促肾上腺皮质激素释放激素2、尿皮质素/UTS1、尿皮质素2和尿皮质素3。这些基因在表达模式以及受体亲和力方面存在差异，使它们能够在各种物种中发挥广泛的功能。为了更好地了解这些基因在单一物种中的作用，我们研究了它们在丽鱼科鱼类伯氏中丽鱼中的表达模式。通过原位杂交来绘制大脑中crhb、uts1、ucn2和ucn3的mRNA表达模式，揭示了表达的保守和独特空间特征。表达crhb和uts1的细胞分布最广泛，有几个共同区域化的区域。ucn3含量较少，但在整个大脑范围内的离散区域中发现，在小脑中表达较高，而ucn2仅局限于少数区域。逆转录聚合酶链反应表明，虽然crhb、uts1和ucn3在几种身体组织中都有发现，并且在大脑中广泛分布，但ucn2在大脑中的分布非常有限，而crha仅在眼睛中表达。贝叶斯系统发育分析确定了尿皮质素家族中的详细关系和新的直系同源基因。我们发现一些爬行动物中存在尿皮质素2基因缺失的证据。我们对模式生物中枢神经系统中完整基因家族的详细描述将为未来关于这些基因在伯氏中丽鱼中功能的研究提供信息，并为与硬骨鱼和其他脊椎动物的比较研究奠定基础。
