The insertion of a full‐length Bos taurus LINE element is responsible for a transcriptional deregulation of the Normande Agouti gene

Abstract

Mammalian pigmentation is controlled by the concerted action of Tyr, Tyrp1 and Dct producing eumelanin and/or pheomelanin in melanocytes. The ratio of these two pigments is determined by the agonist alpha-melanocyte stimulating hormone and the antagonist Agouti protein acting on the Mc1r. Here we show that the Agouti gene is over-expressed in Normande breed compared with Prim'Holstein breed. The Normande cattle have a characteristic coat color phenotype with a variable presence of black (eumelanin) hair over a red/brown background. We have found a previously undescribed full-length L1-BT element inserted in the 5'-genomic sequence of the Agouti gene in Normande cattle which promotes the over-expression of alternative transcripts. The variable expression of the alternative transcript directed by the long interspersed nuclear element promoter may be the origin of the brindle coat color pattern of the Normande breed. This new bovine Agouti allele isolated in Normande breed has been named Abr. Finally, as ectopic over-expression of Agouti in Ay mice is responsible for the obesity syndrome, we discuss the possible consequences of Abr for meat and milk production in cattle.

A gene duplication affecting expression of the ovine ASIP gene is responsible for white and black sheep

“…The expression of the mouse ASIP gene ordinarily is tightly spatially and temporally regulated and restricted primarily to the skin (Bultman et al 1992). In humans, , cattle (Girardot et al 2005(Girardot et al , 2006, and, as we have now shown, in domestic sheep, ASIP is more widely expressed with various transcripts identified from several tissues. While there are no apparent negative effects of this ubiquitous ASIP expression in sheep, the possible consequences of the wider tissue expression is still to be investigated.…”

The untranslated side of hair and skin mammalian pigmentation: Beyond coding sequences

“…In sheep, levels of ASIP mRNA were reported to be significantly different between black and white animals (34). In bovine, we reported significantly different levels of expression of Tyrosinase, Tyrosinase protein 1 (Trp1), ASIP, and Dopachrome tautomerase (Dct, also known as Trp2) in black, brown, brindle, and white coat colors (35).…”

Coat Color Patterns and Genotypes of Extension and Agouti in Hanwoo and Jeju Black Cattle

“…To analyze ASIP genotypes for the presence/absence of an1.2 kb L1-BT retroposon, the ASIP gene was amplified using specific primers (Table 1) designed by Girardot et al [6]. The presence of an L1-BT element in ASIP was detected on 1.5% agarose gels.…”

“…The underlined nucleotide sequences of MC1RmisF and MC1RmisR were modified to replace the AciⅠ recognition site at MC1R g.296T>C with that of AluⅠ for genotyping because components of the PCR reaction buffer usually inhibit the digestion activity of the AciⅠ restriction enzyme [27]. Recently, a bovine agouti allele for brindle coat color was described in the Normande cattle breed by an L1-BT insertion between the skin-specific promoter and the first coding exon for the ASIP gene [6,7]. Previous MC1R studies Amplified products were enzymatically digested with 2 restriction enzymes (AluI for g.296T>C; MspI for g.310delG).…”