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United States Department of Agriculture

Agricultural Research Service

Title: Cloning of Turkey Insulin-Like Growth Factor-I (Igf-I)

Authors
item Czerwinski, Susan
item Ashwell, Christopher
item McMurtry, John

Submitted to: Genbank
Publication Type: Abstract Only
Publication Acceptance Date: July 12, 1998
Publication Date: N/A

Technical Abstract: The polypeptide hormone insulin-like growth factor-I (IGF-I) is an important regulator of development, growth, and metabolism in vertebrates. IGF-I function has recently been described in avian species, specifically chickens. Using a reverse transcriptase-polymerase chain reaction (RT-PCR) based approach, we have identified and cloned the IGF-I homolog present in the turkey. Total RNA was isolated from the liver of an adult male, revers transcribed with oligo dT primer, and amplified by polymerase chain reaction using two overlapping pairs of oligonucleotide primers based on the chicken IGF-I cDNA sequence. The resulting amplification products were cloned and sequenced. The turkey IGF-I cDNA sequence was submitted to the GenBank database and cataloged by the ascension designation (AF074980). This sequence includes the entire coding region and differs by 6 out 626 bases from that of chicken IGF-I. The predicted amino acid sequence of the precursor protein differs by two conservative amino acid substitutions of alanine for glycine at position 36 and leucine for valine at position 136. These changes occur in the N-terminal and C-terminal regions of the Pro-peptide which is removed by post-translational processing to form the biologically active peptide (amino acids 49-118) which is identical to chicken IGF-I. The sequence of turkey IGF-I will allow for further study of its regulation of expression, support the use of homologous assays for the measurement of IGF-I, and contribute to the understanding of its multi-functional role in reproduction and metabolism.

Last Modified: 7/22/2014
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