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Characterization of Pituitary Protein Expression Patterns During Stages in the Reproductive Cycle of Turkey Hens
Spellerberg, Amy Marie
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Improvements in turkey reproductive efficiency is a very desirable goal for the turkey industry. The ability to maintain turkey hens in the egg-laying (LAY) stage and produce one additional egg per hen a year is estimated to save the turkey industry approximately $1.5 million dollars per year. Overall protein expression generated by tissues of the hypothalamic-hypophyseal complex, namely the anterior pituitary, of the mature turkey hen have a profound impact on reproductive cycling (Scanes, 2000). One of the key physiological factors produced by the anterior pituitary and shown to play a significant role in the regulation of egg laying is the protein prolactin (Prl). The objectives for this study are to examine the overall protein expression patterns from turkey hen pituitary tissue during the nonphotostimulated (NPS), photostimulated (PS), and egg laying (LAY) stages. Attempts to isolate transcription factors that regulate the expression of Prl using an affinity chromatography technique or southwestern screening of a bacteriophage expression library were not successful. A global analysis of protein expression, using two-dimensional polyacrylamide gels (2D gels), was conducted using whole cell, cytoplasmic and nuclear protein extracts from pituitary tissue collected during the NPS, PS and LAY reproductive stages. Approximately 1,046 proteins ranging in pI from 4.6-8.2 and molecular weights between 100 kDa-6kDa were resolved. Protein expression patterns were replicated and verified using pituitaries harvested from NPS, PS and LAY stage turkey hens from another laboratory. Proteins showing considerable changes (563 proteins increased in expression and 98 proteins decreased in expression from the NPS to the LAY stage) in their expression between the reproductive stages were grouped in analysis sets for future identification. These proteins may prove to be important to the reproductive cycling of the turkey hen and warrant future investigation. The results of this study contribute to the overall understanding of the role that the pituitary, as a critical part of the hypothalamic-hypophyseal complex, plays in turkey hen reproductive cycling.
- Masters Theses