Cloning, sequencing, and expression of a subset of selenoprotein transcripts in the turkey (Meleagris gallopavo)

We recently reported that the minimum Se requirement for male turkey poults is 0.3 μg Se/g – three times higher than requirements found in rodent – based on liver and gizzard Gpx4 and Gpx1 activities (Exp Biol Med 235:23 (2010)). We also found that levels and Se regulation of Gpx4 activity and mRNA in turkeys are distinct from those in mammals. Thus we initiated cloning of turkey selenoprotein transcripts as a preliminary step to investigate Se regulation of the full selenoproteome. Using homology of mammalian and G. gallus (chicken) transcripts and proteins, primers for qRT‐PCR were designed to examine the relative expression of selenoproteins in total RNA isolated from 6 turkey tissues (liver, heart, kidney, gizzard, thigh, breast) of an adult male Nicholas‐strain (white) turkey. Fold‐changes in different tissues relative to liver were: for kidney, Gpx1 11X, Txnrd1 4X, Sepn1 3X, Sepw1 3X; for heart, Sepw1 6X, Sepn1 4X, Dio2 4X; for gizzard, Sepn1 6X, Selm 3X, Sepw1 2X; for breast, Sepw1 6X; for thigh, Sepw1 4X, Dio2 3X, Sepn1 2X. 3ˈ‐RACE was used to clone and sequence 17 selenoproteins, including 5 selenoproteins (Gpx3, Sepp1, Sepp2, Sepw1, Sep15) currently not predicted by the 2010 next‐generation sequencing of the turkey genome (PloS Biology 8:e1000475 (2010)). These sequences will be used to develop molecular biomarkers to characterize Se regulation in the turkey. (UW Hatch WI04909 and Selenium Nutrition Research Fund)