Developmental changes of Insulin-like growth factors in the liver and muscle of chick embryos

Abstract

The insulin-like growth factors ( IGFS: ) are synthesized in tissues and play an important role in embryonic development of avian via autocrine/paracrine mechanisms. In the study, mRNA expression of IGFs were detected by real-time PCR in the muscle and liver from d 10 to 20 of chick embryo ( E10: to E20: ). Methylation of IGF1 promoter in the muscle was analyzed by bisulfite sequencing PCR as well as IGF2 promoter in the liver. These results showed that there was obviously IGF1 expression in liver at E19 and E20. The higher IGF1 expression in muscle was found during E15 to E18 with the peak on E17, and then declined. Correspondingly, the lowest methylation level of IGF1 promoter was detectable on the same embryonic d 17. Expression of IGF2 in muscle increased gradually during embryonic growth and showed higher level in the later stages (E17 to E20) when IGF1 expression began to decrease. IGF2 expression in liver reached the first peak on E14, then declined but gradually elevated from E17. IGF2 promoter methylation in liver showed gradual decline on d 12, 15, 17 and 19 of incubation, meanwhile IGF2 expression of liver increased gradually. These results suggested that IGF1 and IGF2 might separately be more important for muscle and liver growth in chick embryonic development. Variation of IGFs expression during the incubation might be concerned with the methylation of gene promoter. The profile of IGFs expression in chick embryonic tissues may be meaningful for understanding organ growth and embryonic development in chick.

Comparative Proteomic Analysis of Chicken Primary Hepatocytes with Folic Acid Free or Supplementation Culture Mediums.

“…DNA methylation is catalyzed by DNA methyltransferases (DNMTs). DNMT1 is a maintenance methyltransferase and responsible for restoring the methylated status of newly synthesized daughter strands; DNMT3a and DNMT3b are de novo methyltransferases (Li et al, 2016). Consistently, these DNMTs expression were also not affected by folic acid supplementation in the current study.…”

“…Primers sequences were shown in table 1. Detailed procedures were operated as our previous description (Liu, et al, 2016). The 2 −ΔΔ Ct method was used for gene relative expression (Livak and Schmittgen, 2001).…”

Insulin-Like Growth Factor (IGF) System in Liver Diseases

“…In addition to its key role in whole-body, glucose and lipid homeostasis, this organ is also a major site of the synthesis of plasma proteins and endocrine factors such as insulin-like growth factor 1 and 2 (IGF1 and IGF2), as well as their binding proteins (IGFBPs) and thereby influences whole-body metabolism and growth [ 1 ]. The circulating IGFs do not represent the true level of tissue secretion, though they may reflect organ development to some extent [ 2 ]. Moreover the role of the liver in the secretion of IGF1 and IGFBPs, is not only under endocrine and nutritional control, but also under autocrine and paracrine control [ 3 ].…”

Deep RNA sequencing of pectoralis muscle transcriptomes during late-term embryonic to neonatal development in indigenous Chinese duck breeds

“…During development, both cTNNC and sTNNC are expressed in embryonic skeletal muscle, but expression of the cTNNC gene is subsequently turned off during the transition to fast-twitch muscle[ 27 ]. IGFs are synthesized in tissues and play an important role in embryonic development in birds via autocrine/paracrine mechanisms[ 28 ]. Higher IGF1 expression levels were found in muscle from E15-E18 with a peak at E17 followed by a decline during chick embryonic development[ 28 ].…”

“…IGFs are synthesized in tissues and play an important role in embryonic development in birds via autocrine/paracrine mechanisms[ 28 ]. Higher IGF1 expression levels were found in muscle from E15-E18 with a peak at E17 followed by a decline during chick embryonic development[ 28 ]. We previously reported that IGF1 and MSTN mRNA levels may influence muscle-growth rates in ducks[ 3 ].…”