The germ cell marker dead end reveals alternatively spliced transcripts with dissimilar expression

Ana Carina Nogueira Vasconcelos,Danilo Pedro Streit,Goro Yoshizaki,Anna Octavera,Misako Miwa,Naoki Kabeya

doi:10.1038/s41598-019-39101-9

Abstract

Since the late 19th century, the Amazon species Colossoma macropomum (tambaqui) has been exploited commercially and the climate change has contributed to decline in tambaqui numbers. Although germ cell cryopreservation and transplantation can help preserve the species’ genetic resources semipermanently, its germ cell behavior has not been analyzed to date. In this study, we isolated the tambaqui’s dead end gene (dnd) homolog (tdnd) and used it as a molecular marker for germ cells to obtain basic information essential for transplantation. The amino acid sequence showed 98% similarity and 53% identity with the zebrafish dnd. Phylogenetic analysis and the presence of consensus motifs known for dnd revealed that tdnd encodes the dnd ortholog and its transcript is detectable only in the testes and ovaries, showing a strong positive signal in oocytes and spermatogonia. The tambaqui possesses, at least, three different transcripts of tdnd which show dissimilar expression profile in undifferentiated and sexually mature animals, suggesting that they play distinct roles in germline development and they may influence the choice of donors for the cell transplantation study.

Highlights

Eukaryotic gene expression control is complex and refined, and virtually all cells of multicellular organisms have the same expression potential
The Dnd protein has been shown to bind to the 3′-untranslated region of messenger ribonucleic acid (mRNA) to displace micro-RNAs that bind to adjacent sites on the same mRNA11
We inferred that the amino acid sequence encodes 398 amino acid residues and has three RNA recognition motifs (RRMs): RRM1 (AA 52–129), RRM2 (AA 131–211), and double-stranded RRM (DSRM) (AA 314–394) (Fig. 1)

Summary

Introduction

Eukaryotic gene expression control is complex and refined, and virtually all cells of multicellular organisms have the same expression potential. Most gene expression controls are performed at transcription and translation levels, their fine-tuning is performed by alternative processing of messenger ribonucleic acid (mRNA) precursors, generating different forms of mature mRNAs, depending on the cell type[1,2]. Alternative splicing of precursor mRNA is a crucial mechanism for expanding gene expression complexity and plays a substantial role in cellular differentiation and organism development. This important form of gene regulation contributes to gene expression control and increases protein diversity[2,5,6]. The germ cell transplantation could be used as an alternative to preserve genetic resources of important fish species, such as Colossoma macropomum from the Amazon and Orinoco river basins in northern South America. Only 1% of the fish in the natural environment have the size allowed for fishing (i.e., 55 cm), showing that the species’ exploitation is above the maximum sustainable yield[30]

Methods

Results

Conclusion