Egg perivitelline fluid proteome of a freshwater snail: Insight into the transition from aquatic to terrestrial egg deposition

MU, HUAWEI; QIU, JIAN?WEN; ZHANG, YANJIE; IP, JACK C.H.; HERAS, HORACIO

RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM.

JOHN WILEY & SONS LTD

Año: 2020 vol. 34

0951-4198

Rationale: Proteins from the egg perivitelline fluid (PVF) are assumed to play critical roles in embryonic development, but for many groups of animals their identities remain unknown. Identifying egg PVF proteins is a critical step towards understanding their functions including their roles in evolutionary transition in habitats.Methods: We applied proteomic and transcriptomic analysis to analyse the PVF proteome of the eggs of Pomacea diffusa, an out-of-water ovipositing freshwater snail in the family Ampullariidae. The PVF proteins were separated with SDS-PAGE method, and proteomic analysis was conducted using LTQ Velos Ion Trap Mass Spectrometer coupled with liquid chromatography. Comparison of PVF proteomes and evolution analyses were performed between P. diffusa and other ampullariids.Results: In total, 32 egg PVF proteins were identified from P. diffusa. They were categorized as PV1-like subunits, immune responsive proteins, protein degradation, signaling and binding, transcription and translation, metabolism, oxidation-reduction and unknown function. Interestingly, the proteome includes a calcium binding protein important in forming the hard eggshell that enabled the terrestrial transition. However, it does not include PV2, a neurotoxic protein that was assumed to be present in all Pomacea species. Conclusions: The PVF proteome data from P. diffusa can help us better understand the roles of reproductive proteins played during the transition from underwater to terrestrial egg deposition. Moreover, they could be useful in comparative studies of the terrestrialization in several groups of animals that occurred independently during their evolution.