Proteomic analysis during larval development and metamorphosis of the spionid polychaete Pseudopolydora vexillosa

Flora Sy Mok,Pei-Yuan Qian,Vengatesen Thiyagarajan

doi:10.1186/1477-5956-7-44

Abstract

BackgroundWhile the larval-juvenile transition (metamorphosis) in the spionid polychaete Pseudopolydora vexillosa involves gradual morphological changes and does not require substantial development of juvenile organs, the opposite occurs in the barnacle Balanus amphitrite. We hypothesized that the proteome changes during metamorphosis in the spionids are less drastic than that in the barnacles. To test this, proteomes of pre-competent larvae, competent larvae (ready to metamorphose), and juveniles of P. vexillosa were compared using 2-dimensional gel electrophoresis (2-DE), and they were then compared to those of the barnacle.ResultsUnlike the significant changes found during barnacle metamorphosis, proteomes of competent P. vexillosa larvae were more similar to those of their juveniles. Pre-competent larvae had significantly fewer protein spots (384 spots), while both competent larvae and juveniles expressed about 660 protein spots each. Proteins up-regulated during competence identified by MALDI-TOF/TOF analysis included a molecular chaperon (calreticulin), a signal transduction regulator (tyrosin activation protein), and a tissue-remodeling enzyme (metallopeptidase).ConclusionsThis was the first time to study the protein expression patterns during the metamorphosis of a marine polychaete and to compare the proteomes of marine invertebrates that have different levels of morphological changes during metamorphosis. The findings provide promising initial steps towards the development of a proteome database for marine invertebrate metamorphosis, thus deciphering the possible mechanisms underlying larval metamorphosis in non-model marine organisms.

Highlights

While the larval-juvenile transition in the spionid polychaete Pseudopolydora vexillosa involves gradual morphological changes and does not require substantial development of juvenile organs, the opposite occurs in the barnacle Balanus amphitrite
The proteome of Pseudopolydora vexillosa larvae Most of the protein spots in the 3 developmental stages were in the range of pI 4-7 and concentrated in the molecular weight range of 14-90 kDa (Fig. 2)
A previous study on proteome changes during marine invertebrate metamorphosis found a dramatic reduction in the number of proteins expressed after settlement but did not see extensive de novo synthesis of proteins during larval metamorphosis in the barnacle Balanus amphitrite [20]

Summary

Introduction

While the larval-juvenile transition (metamorphosis) in the spionid polychaete Pseudopolydora vexillosa involves gradual morphological changes and does not require substantial development of juvenile organs, the opposite occurs in the barnacle Balanus amphitrite. Marine invertebrates have a biphasic life cycle that includes a pelagic larval stage that is morphologically distinct from the adult form [1]. Their larvae typically metamorphose into juveniles or adults simultaneously with or directly following settlement out of the water column; they will subsequently colonize and structure the benthic communities [2]. The morphological, behavioural, and differential gene expressions during larval metamorphosis have been wellstudied among some marine invertebrates [11,12,13], but relatively fewer studies focus on comparing the commonalities and differences underlying the metamorphic processes between different marine invertebrates [7]. Even fewer studies focus on the protein expressions in marine invertebrate metamorphosis [14]

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Discussion

Conclusion