The microstructural, mineralogical and transcriptional developments of shell biomineralization of Pinctada maxima. Series GSE14305.

Molluscan larval ontogeny is a highly conserved process typical of 3 principal developmental stages. A characteristic unique to each of these stages is shell design, termed prodissoconch I, prodissoconch II and dissoconch. These shells vary in morphology, mineralogy and microstructure. The discrete temporal transitions in shell biomineralization between these larval stages are utilized in this study to investigate transcriptional involvement in several distinct biomineralization events. Scanning electron microscopy and X-ray diffraction analysis of P. maxima larvae and juveniles collected throughout post-embryonic ontogenesis, document the mineralogy and microstructure of each shelled stage as well as establishing a timeline for transitions in biomineralization. P. maxima larval samples most representative of these biomineralization distinctions and transitions were analyzed for differential gene expression on the microarray platform PmaxArray 1.0. A number of transcripts are reported as differentially expressed in correlation to the mineralization events of P. maxima larval ontogeny. Some of those isolated are known shell matrix genes while others are novel, these are discussed in relation to potential shell formation roles. This interdisciplinary investigation has married the shell developments of P. maxima larval ontogeny with corresponding gene expression profiles, furthering the elucidation of shell biomineralization.Microarray is used to examine the temporal differential expression of transcripts from several bivalve larval development stages including 24hrs post fertilization, 3 days, 17 days, 20 days, 23 days, 26 days, 30 days, 35 days, 40 days. Differential expression profiles for transcripts of all the temporal samples was determined based on comparison to a common reference of unfertilized eggs. Each temporal larval sample included in the study has at least 3 replicate hybridizations. Dye flips have been incorporated in the replicates. A total of 46 microarray hybridizations were performed in this investigation for differential expression analysis.

软体动物幼虫发育（Molluscan larval ontogeny）是一类高度保守的过程，具备三个典型的主要发育阶段。这三个阶段各自独有的标志性特征为壳体结构，分别被命名为原壳Ⅰ（prodissoconch I）、原壳Ⅱ（prodissoconch II）与成壳（dissoconch）。这些壳体在形态学、矿物学与微观结构层面均存在显著差异。本研究借助这些幼虫发育阶段间壳体生物矿化的离散时间转变，探究转录调控在多项特异性生物矿化事件中的参与作用。本研究通过扫描电子显微镜与X射线衍射分析，对整个胚胎后发育周期中采集的大珠母贝（P. maxima）幼虫及幼体进行检测，明确了各壳体阶段的矿物学与微观结构特征，并确立了生物矿化转变的时间线。选取最能体现上述生物矿化差异与转变过程的大珠母贝幼虫样本，采用PmaxArray 1.0微阵列（microarray）平台开展差异基因表达分析。本研究报道了一批与大珠母贝幼虫发育阶段矿化事件相关的差异表达转录本（transcript）。其中部分分离得到的转录本已被注释为壳体基质基因，其余则为全新序列，本文将结合其潜在的壳体形成功能对这些基因展开讨论。此项跨学科研究将大珠母贝幼虫发育的壳体形成过程与对应基因表达谱相结合，进一步阐明了壳体生物矿化的分子机制。
本研究采用微阵列（microarray）技术，对多个双壳类幼虫发育阶段的转录本进行时间维度的差异表达分析，涵盖受精后24小时、3天、17天、20天、23天、26天、30天、35天及40天的样本。所有时间梯度样本的转录本差异表达谱，均以未受精卵作为共同参照进行比对确定。本研究纳入的每个时间梯度幼虫样本均至少设置3次重复杂交，并在重复实验中引入了染料翻转（dye flips）实验设计。本次差异表达分析共计完成46次微阵列杂交实验。