Expression and cellular localization of insulin-like growth factor-II protein and mRNA in Sparus aurata during development

Abstract

The spatial localization of IGF-II protein and mRNA was investigated during larval and postlarval developmental stages of the gilthead sea bream (Sparus aurata) by immunohistochemistry and in situ hybridization, using specific antisera and riboprobes. Steady-state levels of IGF-II mRNA in larvae were determined by Northern blot analysis and were found to be increased. Immunoreactivity towards IGF-II was found in larval skin, muscle, gills, gut, olfactory epithelium and kidney. After metamorphosis, the strongest immunoreactivity was found in red skeletal muscle. Positive reaction with IGF-II antibodies was also found in the olfactory epithelium and in the epithelia of pharynx, oesophagus, stomach and kidney. In the adult, the most intense signal was observed in the red and pink musculature and in heart musculature. Immunostaining was also found in saccus vasculosus, thymus, spleen and ovary. IGF-II mRNA was detected by in situ hybridization in the brain, olfactory epithelium, eye, pharynx, skeletal musculature and liver. The spatial distribution of IGF-II shown in this study is consistent with previous findings on the cellular localization of IGF type 1 receptor in the sea bream and supports a role for IGF-II during development and growth of sea bream. Furthermore, these results suggest that IGF-II acts in an autocrine/paracrine manner.

Cellular localisation of insulin-like growth factor binding protein-2 (IGFBP-2) during development of the marine fish, Sparus aurata

“…This idea is supported by the similar pattern, in general, of cellular localisation of IGFBP-2 (reported here) to that of IGF-I and IGF-II found in the seabream and shi drum (Funkenstein et al 1997;Perrot et al 1999;Radaelli et al 2003aRadaelli et al , 2003b. However, the use of immunohistochemistry and in situ hybridisation in the current study has enabled us to identify the pattern of expression in various cell types within individual tissues and organs.…”

“…Despite this advance in IGFBP research in fish over the past few years and the growing evidence for the expression of IGFs and IGF-Rs in a various tissues in many fish species (Richardson et al 1995;Reinecke et al 1997;Perrot et al 1999;Funkenstein et al 2002;Radaelli et al 2003aRadaelli et al , 2003b, information regarding the role of IGFBPs in fish development, growth and reproduction is relatively scarce. Northern blot and reverse transcription/polymerase chain reaction (RT-PCR) analyses have demonstrated IGFBP-2 expression during the early developmental stages and in the developing gonad of seabream (Funkenstein et al 2002).…”

Allelic expression of IGF2 in live-bearing, matrotrophic fishes

“…2. Developmental and physiological studies of IGF2 action in several fish species have established the important role of this hormone in promoting growth during embryogenesis and throughout the life of teleost fishes (Greene and Chen 1997;Radaelli et al 2003;Reinecke and Collet 1998). Taken in conjunction with the high level conservation of IGF2 amino acid sequence among vertebrates, these observations argue for a conserved role for this gene in development.…”

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).…”