The nme gene family in zebrafish oogenesis and early development

Abstract

After the recent report of the expression of several nme genes in the zebrafish gonads, the present study aimed at further analyzing the expression of nme genes in the ovary with special attention for the nme transcripts that are maternally inherited and could thus participate in the determination of oocyte developmental competence. The expression levels of all groups I and II nme genes were characterized by QPCR in a panel of zebrafish tissues. The nme genes exhibiting an ovarian expression were subsequently monitored throughout oogenesis and early development, and their expression sites characterized using in situ hybridization. Here, we show that nme2b1, nme3, nme4, and nme6 are highly expressed in the ovary and present in the zebrafish oocyte throughout oogenesis. While the four transcripts are maternally inherited, nme3 and nme6 display a typical maternal profile and are detected in the zebrafish early embryo. In contrast to nme3, nme6, abundance exhibits a sharp decrease during early embryogenesis. After zygotic genome activation, we observed an increased expression of nme2b1, nme2b2, nme3, and nme6. The present study provides a comprehensive overview of the expression of nme family members during zebrafish oogenesis and early development. In addition, the maternal origin of two nme transcripts in the early embryo is reported here for the first time in any vertebrate species. Together, our observations suggest an important role of the nme family in oocyte and embryo development in vertebrates.

Glucose metabolism ontogenesis in rainbow trout (Oncorhynchus mykiss) in the light of the recently sequenced genome: new tools for intermediary metabolism programming

“…Samples were homogenized using Precellys ® 24 (Bertin Technologies, Montigny-le-Bretonneux, France): (1) in 7 ml tubes containing Trizol reagent (Invitrogen, Carlsbad, CA, USA) and 2.8 mm ceramic beads for 2×30 s, separated by 15 s, at 5500 rpm for oocytes and embryos (30 per sample and per spawn); and (2) in 2 ml tubes containing Trizol reagent (Invitrogen) and 2.8 mm ceramic beads for 2×20 s, separated by 15 s, at 5500 rpm for alevins (1 alevin per tube, 6 alevins per spawn/diet for mixed and exogenous feeding fish). Luciferase control RNA (Promega), 10 pg per 1.9 mg of embryo/alevin or oocyte, was added to each sample to allow for data normalization during early development as previously described (Desvignes et al, 2011;Marandel et al, 2012). Total RNA was then extracted according to the manufacturer's instructions.…”

nanog 5′-upstream sequence, DNA methylation, and expression in gametes and early embryo reveal striking differences between teleosts and mammals

“…One pg of Luciferase Control RNA (Promega, L4561) per embryo or oocyte was added to each sample prior to tissue homogenization in Trizol in order to allow data normalization using an external calibrator as previously described (Desvignes et al, 2011). Based on the weight of 24 hpf embryos, 1 pg of luciferase was also added per 1.9 mg fin.…”

“…Whole mount in situ hybridization (WISH) was carried out as previously described in zebrafish (Desvignes et al, 2011) with minor modification. DIG-11-UTP labeled sense and antisense RNA probes were generated from the same plasmid clone containing 830 bp goldfish nanog cDNA fragment (representing the part 138-968 of the submitted sequence (Genbank ID: JF773571).…”

Fitness of early life stages in F1 interspecific hybrids between Dicentrarchus labrax and D. punctatus

“…These include several extrinsic factors that can modify the female endocrine status during oogenesis, such as physicochemical parameters of water, photoperiod (Bromage et al 1992(Bromage et al , 1994, the amount and quality of ingested food (Watanabe and Kiron 1995), broodstock stress and the over-ripening of eggs after ovulation (Campbell et al 1992, Christiansen and Torrisen 1997. The intrinsic properties of the egg, such as its genes, the nutrients in the yolk sac, and the contribution of the parental transcripts and proteins after fertilisation, can also determine the egg quality (Brooks et al 1997;Aegerter et al 2005;Bonnet et al 2007aBonnet et al , 2007bCrespel et al 2008;Desvignes et al 2011). In addition, the incubation environment also affects the success of production of viable offspring, both in the wild and in captivity (Lam 1994;Nagahama 1995).…”