SOCS1 and SOCS3 are the main negative modulators of the somatotrophic axis in liver of homozygous GH-transgenic zebrafish (Danio rerio)

Cloning of common carp SOCS-3 gene and its expression during embryogenesis, GH-transgene and viral infection

“…Regulation of the GH intracellular signalization pathway occurs through a complex mechanism involving the coordinated action of various negative regulators, whose main targets apparently are JAKs and STATs phosphorylated by activated GHR [33]. The studies by Studzinski et al with two mechanisms indicated that the GH intracellular signalling control observed in HO GH-transgenic zebrafish utilizes SOCS-1 and SOCS-3 [19]. In general, SOCS protein level is rapidly induced by stimulation with different cytokines or growth factors including GH [34].…”

“…However, the expression characterization of teleost SOCS-3 gene at the early embryonic stage remains unknown, and as yet, there is no evidence that SOCS-3 is involved in anti-virus defence of teleost. Recently, the analysis studies showed that SOCS-3 gene was significantly upregulated (4.3-fold) in the liver of homozygous GH-transgenic zebrafish (presented smaller growth in relation to the hemizygous individuals, and similar to non-transgenics) comparing with nontransgenics, suggesting that in the homozygotes, GH signalling is reduced by the action of the SOCS-3 protein [19]. But, little is known about the expression of SOCS-3 gene in the hemizygous individuals.…”

Depletion of suppressor of cytokine signaling-1a causes hepatic steatosis and insulin resistance in zebrafish

“…The upregulated expression levels of socs1a have been reported in GH-overexpressing transgenic zebrafish previously, suggesting that SOCS1a could be also a negative modulator of the somatotrophic axis in zebrafish (13,39). GH signaling is known to stimulate gluconeogenesis, lipolysis, and adipose tissue mobilization in mammals and teleosts (26,28,36).…”

“…The expression of zebrafish socs1a may be induced by LPS and poly I:C, suggesting its potential roles as an inhibitor of IFN signaling (30). However, it has also been reported that socs1a may also be significantly stimulated in the livers of GH-or GH receptor-overexpressing transgenic zebrafish, indicating its involvement in teleost GH signaling pathways (13,39).…”

Activation of GH signaling and GH-independent stimulation of growth in zebrafish by introduction of a constitutively activated GHR construct

“…GH transgenesis has shown to result in different effects of growth enhancement in host fish depending on different genetic backgrounds (Devlin et al 2001(Devlin et al , 2009). For instance, one report showed that GH transgenesis is effective to growth only in hemizygous but not in homozygous individuals of those transgenic zebrafish (Studzinski et al 2009) and we have never obtained fast-growing transgenic zebrafish in our laboratory by GH transgenesis.…”