Effects Of Temperature Stress And Food Deprivation On GH,GHR1 And GHR2 Gene Expression In Snubnose Pompano (Trachinotus Blochii)

Growth hormone(GH)is an important protein hormone,in the process of Growth,reproduction,metabolism,osmotic adjustment of vertebrates.The first step in the growth hormone is binding to the growth hormone receptor(GHR).In the present study,the Snubnose pompano GHR1 and GHR2 genes were cloned,detected in various tissues of Snubnose pompano.We also studied the effects of temperature and fasting on Snubnose pompano,attained the results of the experiment as follows:1.The total length of cDNA of GHR1 and GHR2 genes was cloned from the liver of Snubnose pompano.The full length of the Snubnose pompano GHR1 cDNA is 2334 bp,including 5 'UTR,157bp,3' UTR 269bp,and open reading frame 1908bp,encoding 635 amino acids.The full length of Snubnose pompano GHR1 cDNA is 2248 bp,containing 5 'UTR 176bp,3' UTR 314bp and open reading frame 1758bp,encoding 585 amino acids.The nucleotide sequence of spGHR1 and spGHR2 had 51.2%similarity,and the amino acid sequence was 54.7%.Like other vertebrates,spGHR1 and spGHR2 gene has some characteristics of GHR gene region,such as the GHR ligand binding FGEFS domain,Boxl and Box2 sequence frame,cysteine residues,tyrosine residues,but spGHR1 contains seven cysteine residues and eight tyrosine residues,and spGHR1 contains five cysteine residues and seven tyrosine residues.Evolutionary tree analysis showed that spGHR1 and spGHR2 genes were grouped together with fish GHR1 and GHR2 genes respectively.2.According to the quantitative real-time PCR analysis,the results had shown that the expression GH of Snubnose pompano was the highest in the pituitary,followed by the heart,muscle and gonad.The expression of Snubnose pompano GHRland GHR2 genes in the liver was the highest,suggesting that the liver was the main place for GH to combine with GHR,followed by muscle and fat,with less expression in the telencephalon,mesencephalon and pituitary.3.At he temperature of 21?,Snubnose pompano GH and GHR1 genes had the highest expression.When the temperature increased to 25 ?,the expression were reduced.As the water temperature rised to 29 ?,their expression increased.But their expression deduced at 33?.On the contrary,Snubnose pompano GHR2 gene expression was higher in 21 ?,deduced at 25 ?.As the temperature raised,the GHR2 gene expression increased,and achieved the high level at33?.It is suggested that the Snubnose pompano GHR1 and GHR2 gene smay have different patterns on temperature stimulation.4.0n day 1 of fasting Snubnose pompano GHR1 gene expression of liver significantly reduced compared with the control group.On day 3 of fasting its expression increased significantly;The expression came back to the control level on day 3 of fasting.Snubnose pompano liver GHR2 gene expression increased significantly compared with control groupom day 1.On day3,it reached the highest expression and returned to the control group level after 1 day after refeeding.The results showed that Snubnose pompano GHR1 is the main binding receptor of GH,and GHR2 may be the main target of GH binding when the body is deprived of food.