Identification of predicted genes expressed differentially in pituitary gland tissue of young growing bulls revealed by cDNA-AFLP technique

Differentially expressed transcript derived fragments (TDFs) of bovine pituitary gland tissue at different developmental ages of Limousine and Hereford bulls were identified by cDNA-AFLP technique. Study revealed comparatively higher differentially expressed transcripts in 6-month Limousine bulls and 12-month Hereford bulls. The BLASTn/p analysis identified 3 and 21 predicted genes which gave significant e-values for Limousine and Hereford respectively, in assembled Bos taurus genome. The identified predicted genes expressed in bovine pituitary gland showed their mapped positions on bovine chromosomes: BTA2, 3, 5, 8, 9, 11, 12, 15-23, 26, and 28, respectively. Results based on TDF annotation identified 10 sequences that have BLAST hits to known annotated bovine genes and 14 sequences to unannotated contig regions in the latest gene Ensembl database Btau_4.0. Two breed specific predicted target genes were validated by qRT-PCR. Within and between breeds, qRT-PCR results revealed highly significant differences in the expression levels of bovine euchromatic histone-lysine N -methyltransferase 1 (EHMT1 ) and NCK adaptor protein 2 (NCK2) predicted genes. Obtained results conclude that cDNA-AFLP is a reliable technique for studying within breed age dependent gene expression patterns.