The nacre color of shells has an effect on the pearl color in Hyriopsis cumingii and is an important indicator for its value. The nacre is part of the shell, and some studies have shown that exosomes of the mantle are involved in the formation of shells. Most of the RNA contained in exosomes are microRNAs (miRNAs); however, little information is available on the roles of exosomes and miRNAs on the formation of nacre color in mussels. In this study, exosomes of mantles were extracted from white and purple mussels. High-throughput Illumina sequencing was performed on the white and purple mussel mantle exosomes, and 7,665,167 and 10,994,115 reads were harvested. Using the standard of |log₂(Fold change)| ≥ 2, and a p value ≤ 0.05, a total of 54 differentially expressed miRNAs were identified. The miRNAs that regulated the target genes (hcApo, HcTyr, HcTyp-1, HcMitf, HcSRCR1, and HcSRCR2) involved in shell color formation were predicted. Moreover, miR-15b negatively regulated hcApo, which plays important roles in the absorption and transport of β-carotene in H. cumingii. These results improve our understanding of the molecular mechanisms of nacre color formation in H. cumingii.

中文翻译：

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三角帆蚌的幔外泌体和微小RNA参与了珍珠层的颜色形成。

贝壳的珠光颜色会影响三角锥藻的珍珠色，并且是其价值的重要指标。珍珠层是壳的一部分，一些研究表明，地幔的外泌体参与了壳的形成。外泌体中包含的大多数RNA是microRNA（miRNA）；然而，关于外来体和miRNA在贻贝中珍珠层颜色形成中的作用的信息很少。在这项研究中，地幔外泌体是从白色和紫色贻贝中提取的。在白色和紫色贻贝幔外泌体上进行了高通量Illumina测序，并获得了7,665,167和10,994,115个读数。使用| log ₂（倍数更改）|的标准 ≥2，且p值≤0.05，共鉴定出54个差异表达的miRNA。预测调控参与壳颜色形成的靶基因（hcApo，HcTyr，HcTyp-1，HcMitf，HcSRCR1和HcSRCR2）的miRNA。此外，miR-15b负调控hcApo，在cumingii。H.中β-胡萝卜素的吸收和运输中起重要作用。这些结果增进了我们对三角帆蚌珍珠层颜色形成的分子机制的理解。