De novo assembly of a transcriptome from the eggs and early embryos of Astropecten aranciacus

Abstract

Starfish have been instrumental in many fields of biological and ecological research. Oocytes of Astropecten aranciacus, a common species native to the Mediterranean Sea and the East Atlantic, have long been used as an experimental model to study meiotic maturation, fertilization, intracellular Ca2+ signaling, and cell cycle controls. However, investigation of the underlying molecular mechanisms has often been hampered by the overall lack of DNA or protein sequences for the species. In this study, we have assembled a transcriptome for this species from the oocytes, eggs, zygotes, and early embryos, which are known to have the highest RNA sequence complexity. Annotation of the transcriptome identified over 32,000 transcripts including the ones that encode 13 distinct cyclins and as many cyclin-dependent kinases (CDK), as well as the expected components of intracellular Ca2+ signaling toolkit. Although the mRNAs of cyclin and CDK families did not undergo significant abundance changes through the stages from oocyte to early embryo, as judged by real-time PCR, the transcript encoding Mos, a negative regulator of mitotic cell cycle, was drastically reduced during the period of rapid cleavages. Molecular phylogenetic analysis using the homologous amino acid sequences of cytochrome oxidase subunit I from A. aranciacus and 30 other starfish species indicated that Paxillosida, to which A. aranciacus belongs, is not likely to be the most basal order in Asteroidea. Taken together, the first transcriptome we assembled in this species is expected to enable us to perform comparative studies and to design gene-specific molecular tools with which to tackle long-standing biological questions.

Comparative transcriptome provides molecular insight into defense-associated mechanisms against spider mite in resistant and susceptible common bean cultivars

“…Relative expression profiles of DEGs in the both resistant and susceptible evaluated using qRT-PCR were in complete agreement with the RNA-Seq data. This is in line with other studies, which showed almost the same level of fold changes between RNA-Seq data and qPCR [67,68].…”

Disassembly of Subplasmalemmal Actin Filaments Induces Cytosolic Ca2+ Increases in Astropecten aranciacus Eggs

“…In mammalian eggs, for example, a sperm-specific isoform PLCζ is accountable for generating Ca 2+ waves at fertilization [31,32]. PLCζ, however, does not seem to exist in the genome or transcriptome of sea urchin and starfish [33][34][35], and the InsP 3 -dependent Ca 2+ increase in the fertilized eggs of echinoderms is mostly attributable to PLCɣ [36][37][38], which is shown to be activated by Src-family kinase that interacts with the SH domain of PLCɣ within 15 sec after fertilization [39][40][41]. Even so, questions still remain on how Src-family kinases are activated by their upstream signaling molecules on the egg surface.…”

A relaxin‐like gonad‐stimulating peptide identified from the starfish Astropecten scoparius

“…Mah and Foltz (2011) have reported in living taxa among the Neoasteroidea that the Asteroidea is divided into two superorders; one for Valvatacea including the orders Valvatida and Paxillosida, and another for Forcipulatacea including the order Forciplatida. Recently, a phylogenetic analysis using cytochrome c oxidase subunit 1 gene revealed that Paxillosida and Valvatida species are involved in the same cluster, but Forcipulatida species are in a different cluster (Musacchia et al, 2017). Altogether, the molecular phylogenetic position of AscRGP and PpeRGP is in good agreement with the latest starfish taxonomy.…”