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Expression of insulin-like growth factor system genes in liver and brain tissue during embryonic and post-hatch development of the turkey.
- Source :
-
Comparative biochemistry and physiology. Part A, Molecular & integrative physiology [Comp Biochem Physiol A Mol Integr Physiol] 2005 May; Vol. 141 (1), pp. 76-86. - Publication Year :
- 2005
-
Abstract
- A molecular cloning strategy employing primer-directed reverse transcription polymerase chain reaction (RT-PCR) was devised to sequence 1300 bp of a turkey liver-derived cDNA corresponding to the complete coding region and the 5'- and 3'-untranslated regions of the insulin-like growth factor (IGF)-II mRNA transcript (GenBank accession no. ). The turkey IGF-II gene codes for a 187 amino acid precursor protein that includes a signal peptide, the mature IGF-II hormone, and a C-terminal extension peptide comprised of 24, 67 and 96 amino acids, respectively. Turkey IGF-II showed greater than 95% sequence identity at both the nucleotide and amino acid level with chicken IGF-II. Expression of IGF-I, IGF-II, IGF type-I receptor (IGF-IR), and IGF binding protein (IGFBP)-2 and -5 genes was quantified relative to an internal 18S rRNA standard by RT-PCR in liver and whole brain tissue on days 14, 16, 18, 20, 22, 24 and 26 of embryonic development, as well as at hatch (H, day 28) and at 3 weeks post-hatching (PH). Expression of liver IGF-I was low throughout embryonic development, but increased more than 8-fold by 3 weeks PH. In contrast, IGF-I was expressed in brain tissue at much higher levels than liver throughout development and this level of expression in brain increased gradually, reaching its highest point at 3 weeks PH. IGF-II was expressed at comparable levels in brain and liver tissue during embryonic development, except for transient increases in liver just prior to hatching (days 24 and 26) and at 3 weeks PH. Expression of IGF-IR declined in brain throughout development reaching its lowest level at 3 weeks PH. In liver, IGF-IR expression was lower than that of brain throughout development. An inverse relationship was observed for the expression of IGF-I and IGF-IR genes in brain, but not in liver, through 3 weeks PH. Expression of the IGFBP-2 gene increased in liver around the time of hatch (days 26-28) and declined by 3 weeks PH, whereas the level of expression of IGFBP-5, which was higher than IGFBP-2, remained fairly constant in both brain and liver throughout the developmental period studied. Our data indicates differential expression of selected genes that comprise the IGF system in the turkey during embryonic and PH growth and development.
- Subjects :
- Amino Acid Sequence
Animals
Base Sequence
Brain embryology
Brain growth & development
Cloning, Molecular
DNA, Complementary genetics
Humans
Insulin-Like Growth Factor II genetics
Liver embryology
Liver growth & development
Molecular Sequence Data
RNA, Messenger analysis
RNA, Messenger genetics
Somatomedins chemistry
Turkeys embryology
Turkeys growth & development
Brain metabolism
Gene Expression Regulation, Developmental genetics
Insulin-Like Growth Factor Binding Proteins genetics
Liver metabolism
Receptor, IGF Type 1 genetics
Somatomedins genetics
Turkeys genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1095-6433
- Volume :
- 141
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Comparative biochemistry and physiology. Part A, Molecular & integrative physiology
- Publication Type :
- Academic Journal
- Accession number :
- 15905111
- Full Text :
- https://doi.org/10.1016/j.cbpb.2005.04.006