Screening for Genes Participating in the Formation of Prismatic and Nacreous Layers of the Japanese Pearl Oyster Pinctada fucata by RNA Interference Knockdown

Daisuke Funabara,Shuichi Asakawa,Shigeharu Kinoshita,Fumito Ohmori,Kaoru Maeyama,Shugo Watabe,Satoshi Kanoh,Kikuhiko Okamoto,Kiyohito Nagai

doi:10.1007/978-981-13-1002-7_41

Daisuke Funabara, Shuichi Asakawa + Show 7 more

Open Access

https://doi.org/10.1007/978-981-13-1002-7_41

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Abstract

Many genes have been identified to participate in the shell formation so far. Nevertheless, the whole picture of the molecular mechanisms underlying the shell formation has remained unknown. In our previous study, we analyzed comprehensively genes expressed in the shell-producing tissues and identified 14 genes to be involved in the shell formation by the RNA interference (RNAi) method. In the present study, we performed further screening to find additional novel genes involved in the formation of the nacreous and prismatic layers. We here selected 80 genes from the EST data as candidates to function in the shell formation, conducted knockdown experiments by the RNAi method, and observed surface appearances on the nacreous and prismatic layers. We newly identified 64 genes that could participate in the shell formation. Taken together with our previous study, 78 genes were supposed to function in the shell formation. These findings indicate that the combination of transcriptome and knockdown analyses is a powerful tool to screen novel genes involved in the shell formation.

Highlights

Many genes have been identified to participate in the shell formation so far
Knockdown of the Pif gene by the RNA interference (RNAi) method induced an abnormal crystal structure of aragonite. This finding confirmed that Pif is really involved in the nacreous layer formation and proved that the RNAi method is useful to study genes involved in shell formation
We selected five genes expressed in the mantle pallium, three highly expressed in the mantle pallium and pearl sac, and six expressed in the mantle edge as candidates to function in shell formation

Summary

Introduction

Many genes have been identified to participate in the shell formation so far. In classical ways, proteins were purified from shells after decalcification and their properties were analyzed. We selected five genes expressed in the mantle pallium, three highly expressed in the mantle pallium and pearl sac, and six expressed in the mantle edge as candidates to function in shell formation. Knockdown experiments for these candidate genes induced abnormal appearances on the inner surface of the shells in the oysters (Funabara et al 2014). These findings demonstrated that a combination of transcriptome analyses and RNAi knockdown is a powerful tool to screen genes involved in the shell formation. We conducted further screening for genes involved in the shell formation of P. fucata using the above method

Materials and Methods

Results

Discussion