An aromatase pseudogene is transcribed in the bovine placenta.

The present investigation is focused on a new, truncated bovine aromatase cytochrome P-450-encoding transcript (bCyp19) which was repeatedly isolated from a placental lambda gt10 cDNA library. Different cDNA probes derived from bCyp19 were used during screenings. The deviant transcript contains areas of considerable sequence homology (89-98%) corresponding to exons II, III, V, VIII and IX of bCyp19. Exons VI and VII are missing. Exon IV is replaced by a bovine repeat sequence motif. Numerous translation stop codons occur within all reading frames, thus suggesting that the transcript does not encode a functional protein. The gene was detected by PCR in the genomes of all animals investigated (n = 38). The experiments demonstrate that the bovine genome contains a non-functional copy (pseudogene, Cyp19 phi) of bCyp19 that is transcribed together with the bCyp19 messenger in the bovine post-parturition placenta.