Coastal Fisheries Division CCA Marine Development Center, Texas Parks and Wildlife Department, 4300 Waldron Rd., Corpus Christi, TX 78418, USA.
Department of Life Sciences, College of Science, Texas A and M University-Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412, USA.
Int J Mol Sci. 2024 Jul 16;25(14):7775. doi: 10.3390/ijms25147775.
Southern flounder skin pigmentation is a critical phenotypic characteristic for this species' survival in the natural environment. Normal pigmentation allows rapid changes of color for concealment to capture prey and UV light protection. In contrast, highly visible hypopigmented pseudo-albinos exhibit a compromised immune system and are vulnerable to predation, sensitive to UV exposure, and likely have poor survival in the wild. Skin and brain tissue samples from normally pigmented and hypopigmented individuals were analyzed with next-generation RNA sequencing. A total of 1,589,613 transcripts were used to identify 952,825 genes to assemble a de novo transcriptome, with 99.43% of genes mapped to the assembly. Differential gene expression and gene enrichment analysis of contrasting tissues and phenotypes revealed that pseudo-albino individuals appeared more susceptible to environmental stress, UV light exposure, hypoxia, and osmotic stress. The pseudo-albinos' restricted immune response showed upregulated genes linked to cancer development, signaling and response, skin tissue formation, regeneration, and healing. The data indicate that a modified skin collagen structure likely affects melanocyte differentiation and distribution, generating the pseudo-albino phenotype. In addition, the comparison of the brain transcriptome revealed changes in myelination and melanocyte stem cell activity, which may indicate modified brain function, reduced melanocyte migration, and impaired vision.
南方比目鱼的皮肤色素沉着是其在自然环境中生存的关键表型特征。正常的色素沉着使它们能够快速变色，从而进行伪装以捕获猎物和保护免受紫外线伤害。相比之下，高度可见的色素减退性假白化个体表现出受损的免疫系统，容易被捕食，对紫外线敏感，在野外的生存能力可能较差。对正常色素沉着和色素减退个体的皮肤和脑组织样本进行了下一代 RNA 测序分析。共使用了 1,589,613 个转录本来鉴定 952,825 个基因，组装了一个从头转录组，其中 99.43%的基因映射到组装上。对比组织和表型的差异基因表达和基因富集分析表明，假白化个体似乎更容易受到环境压力、紫外线照射、缺氧和渗透胁迫的影响。假白化个体受限的免疫反应显示出与癌症发展、信号和反应、皮肤组织形成、再生和愈合相关的上调基因。数据表明，改良的皮肤胶原结构可能影响黑色素细胞的分化和分布，从而产生假白化表型。此外，对大脑转录组的比较揭示了髓鞘形成和黑色素干细胞活性的变化，这可能表明大脑功能发生了改变，黑色素细胞迁移减少，视力受损。
