CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou, 510301, China.
Key Laboratory of Marine Bio-resources Sustainable Utilization, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
Mar Biotechnol (NY). 2018 Apr;20(2):220-245. doi: 10.1007/s10126-018-9800-1. Epub 2018 Mar 15.
Bivalve mollusks exhibit hermaphroditism and sex reversal/differentiation. Studies generally focus on transcriptional profiling and specific genes related to sex determination and differentiation. Few studies on sex reversal/differentiation have been reported. A combination analysis of gonad proteomics and transcriptomics was conducted on Chlamys nobilis to provide a systematic understanding of sex reversal/differentiation in bivalves. We obtained 4258 unique peptides and 93,731 unigenes with good correlation between messenger RNA and protein levels. Candidate genes in sex reversal/differentiation were found: 15 genes differentially expressed between sexes were identified and 12 had obvious sexual functions. Three novel genes (foxl2, β-catenin, and sry) were expressed highly in intersex individuals and were likely involved in the control of gonadal sex in C. nobilis. High expression of foxl2 or β-catenin may inhibit sry and activate 5-HT receptor and vitellogenin to maintain female development. High expression of sry may inhibit foxl2 and β-catenin and activate dmrt2, fem-1, sfp2, sa6, Amy-1, APCP4, and PLK to maintain male function. High expression of sry, foxl2, and β-catenin in C. nobilis may be involved in promoting and maintaining sex reversal/differentiation. The downstream regulator may not be dimorphic expressed genes, but genes expressed in intersex individuals, males and females. Different expression patterns of sex-related genes and gonadal histological characteristics suggested that C. nobilis may change its sex from male to female. These findings suggest highly conserved sex reversal/differentiation with diverged regulatory pathways during C. nobilis evolution. This study provides valuable genetic resources for understanding sex reversal/differentiation (intersex) mechanisms and pathways underlying bivalve reproductive regulation.
双壳贝类表现出雌雄同体和性别反转/分化。研究通常集中于与性别决定和分化相关的转录谱和特定基因。关于性别反转/分化的研究较少。对珍珠贝进行了性腺蛋白质组学和转录组学的组合分析，为双壳贝类的性别反转/分化提供了系统的认识。我们获得了 4258 个独特的肽和 93731 个基因，信使 RNA 和蛋白质水平之间有很好的相关性。在性别反转/分化中发现了候选基因：鉴定出 15 个雌雄个体之间差异表达的基因，其中 12 个具有明显的性别功能。三个新基因（foxl2、β-catenin 和 sry）在雌雄同体个体中表达较高，可能参与了珍珠贝性腺性别控制。foxl2 或 β-catenin 的高表达可能抑制 sry 并激活 5-HT 受体和卵黄蛋白原，以维持雌性发育。sry 的高表达可能抑制 foxl2 和 β-catenin 并激活 dmrt2、fem-1、sfp2、sa6、Amy-1、APCP4 和 PLK，以维持雄性功能。sry、foxl2 和 β-catenin 在珍珠贝中的高表达可能参与促进和维持性别反转/分化。下游调节剂可能不是二态表达基因，而是在雌雄同体个体、雄性和雌性中表达的基因。性别相关基因和性腺组织学特征的不同表达模式表明，珍珠贝可能从雄性转变为雌性。这些发现表明，在珍珠贝进化过程中，性别反转/分化具有高度保守的特征，但调控途径存在差异。本研究为了解双壳贝类生殖调控中的性别反转/分化（雌雄同体）机制和途径提供了有价值的遗传资源。
