Allelic expression of glycine amidinotransferase in early chicken germ cells

Glycine amidinotransferase (GATM) is imprinted in mouse placenta, however, is not imprinted in human and pig. In this study, we found five SNPs and two indel sequences in the chicken GATM gene. We preformed quantitative PCR to analyze GATM expression during embryo development. GATM in 6-day-old embryos was mainly expressed in fetal liver and kidney and GATM in female liver and kidney showed higher expression than in males. When GATM expression was compared between 6-day-old male and female gonads, GATM expression was four times higher in 6-day-old male gonad and when primordial germ cells (PGCs) were separated from 6-day-old male and female gonads by the MACS cell separation method, GATM in male PGCs was expressed more than six times higher than in female PGCs. We also analyzed allelic expression of GATM in 6-day-old embryos (brain, heart, liver, kidney and gonad) and 42-week-old chickens (brain, heart, liver, kidney, testis or ovary) and all the analyzed tissues showed bi-allelic expression of GATM. Collectively, chicken GATM was mostly expressed in fetal liver and kidney and showed higher expression in male gonads and PGCs than in female gonads and PGCs. However, chicken GATM was not imprinted in embryonic tissues (brain, heart, liver, kidney and gonad) or in adult tissues (brain, heart, liver, kidney, testis or ovary).