Messenger RNA stockpile of cyclin B, insulin‐like growth factor I, insulin‐like growth factor II, insulin‐like growth factor receptor Ib, and p53 in the rainbow trout oocyte in relation with developmental competence

Abstract

In the present study, correlations between the oocyte messenger RNA (mRNA) stockpile of Cyclin B, insulin-like growth factor I (IGF-I), insulin-like growth factor (IGF-II), insulin-like growth factor receptor Ib (IGFR Ib), and p53 transcripts and the developmental competence of the oocyte were studied. For this purpose, post-ovulatory ageing was used as a tool to generate oocytes of varying developmental competence. Mature female rainbow trout were held at 12 degrees C and periodically checked for ovulation. Oocytes were collected from each female at ovulation and 5, 14, 21 days later. For each collected egg batch, the abundance of several mRNAs in the oocyte was analyzed by real-time PCR and embryo development was monitored after fertilization. Egg quality was estimated not only through embryonic survival but also by studying the occurrence of specific morphological abnormalities. The present study showed that oocyte post-ovulatory ageing was associated with variations of the relative abundance of several studied transcripts within the oocyte. In addition, the abundance of specific mRNAs could be correlated with either the embryonic survival or the occurrence of malformations. Thus, the abundance of IGFR Ib and Cyclin B transcripts in the oocyte was correlated with the occurrence of morphological abnormalities observed at yolk-sac resorption (negatively for IGFR Ib and positively for Cyclin B), while the maternal stockpile of IGF-I, IGF-II, and IGFR Ib mRNAs was positively correlated with embryonic survival.

Hypoxia delays hematopoiesis: retention of embryonic hemoglobin and erythrocytes in larval rainbow trout,Oncorhynchus mykiss, during chronic hypoxia exposure

“…Primer sets were designed based on the coding sequences for O. mykiss EF1-α (Aegerter et al, 2004) and rainbow trout Hb E subunits α-1, α-2, β-1 and β-2 (Maruyama et al, 1999) using PrimerExpress 2.0 software (Applied Biosystems). Primer pairs and accession numbers are listed in Table 1.…”

Experimental selection for body size at age modifies early-life history traits and muscle gene expression in adult zebrafish

“…In zebrafish, some maternal transcripts were found to persist until the end of the blastula stage whilst others were degraded more slowly and were still present at the segmentation stage, indicating some functional role after the start of zygotic transcription (Mathavan et al, 2005). Ovulatory ageing was used to manipulate the content of maternal mRNA in rainbow trout oocytes (Aegerter et al, 2004). Interestingly, igf1rb content was negatively correlated with the occurrence of morphological abnormalities and igf-I, igf2 and igf1rb levels were positively correlated with embryonic survival (Aegerter et al, 2004).…”

“…Ovulatory ageing was used to manipulate the content of maternal mRNA in rainbow trout oocytes (Aegerter et al, 2004). Interestingly, igf1rb content was negatively correlated with the occurrence of morphological abnormalities and igf-I, igf2 and igf1rb levels were positively correlated with embryonic survival (Aegerter et al, 2004). To our knowledge, no previous studies have investigated whether domestication and/or artificial selection results in changes in the deposition of maternal mRNAs in the yolk.…”

Molecular cloning and single nucleotide polymorphism analysis of IGF2a genes in the common carp (Cyprinus carpio)

“…IGF2 mRNA is abundantly expressed in fetal rats, but the expression declines after birth in most tissues, with the exception of the choroid plexus and meninges, which show high expression (Bondy et al, 1990;Nilsson et al, 1996). The IGF2 gene has also been shown to be abundantly expressed in both hepatic and nonhepatic tissues of juvenile and adult teleosts, including common carp (Tse et al, 2002;Vong et al, 2003), rainbow trout (Bobe et al, 2003;Chauvigne et al, 2003;Gabillard et al, 2003;Aegerter et al, 2004), zebrafish (Maures et al, 2002), daddy sculpin (Loffing-Cueni et al, 1999), tilapia (Caelers et al, 2003), sea bream (Perrot et al, 2000;Radaelli et al, 2003), and rabbitfish (Ayson et al, 2002). In addition, the IGF2 polymorphism has generally been associated with growth, for example, in studies on pig (Stinckens et al, 2010) and tilapia (Yu et al, 2010).…”