Variants in the CYP19A1 gene can affect in vitro embryo production traits in cattle

Abstract

Purpose: This study aimed to associate DNA variants in promoter and exon flanking regions of the CYP19A1 gene with in vitro embryo production traits in cattle. The role of transcription factor binding sites created or lost due to DNA sequence variation and their possible effect on gene expression was also evaluated.

Methods: We collected date from Gyr dairy oocyte donor cows (Bos taurus indicus) at a commercial in vitro embryo production farm and analyzed the genotype-phenotype association with in vitro production traits. Using Sanger sequencing and web-based software, we assessed important CYP19A1 gene regions in oocyte donor cows and analyzed the effects of variants on the transcription factor binding sites.

Results: Two SNP mutations significantly associated with oocyte production, oocyte viability, embryo development, and pregnancies were found (T > C in the untranslated exon 1 flanking region ([GenBank: AJ250379.1]: rs718446508 T > C), and a T > C in the 5'-upstream region (1.1 promoter) ([GenBank: AC_000167.1]: rs41651668 T > C). Six new transcription factor binding sites were created. A binding site for transcription factors associated with the development of the placenta and embryo implantation was eliminated due to variations in the DNA sequence identified.

Conclusions: The CYP19A1 gene contributes to genetic variation of in vitro embryo production traits in cattle. The complexity of the physiological phenomena related to estrogen pathways and their influence on reproduction in cattle allow indication of the mutations evaluated here as possible genetic markers for embryo production traits, which should be validated in the next steps of marker-assisted selection.

Keywords: Embryo transfer; Estrogen; Genetic marker; Oocyte donor; Regulatory element; Transcription factor.

Fig. 1

Identification of DNA variants by Sanger sequencing in CYP19A1 gene of Gyr oocyte donor cows. a Common allele of the untranslated exon 1 flanking region (UE1FR). b Heterozygous mutation of the UE1FR. c Common allele of the 5′-upstream and promoter region (5-UTRPR). d Heterozygous mutation of the 5-UTRPR. e Schematic representation of the promoter regions and associated variants in the bovine CYP19A1 gene (modified output of Genomatix software)

Fig. 2

Schematic representation of promoter 1.1 of CYP19A1 bovine gene and associated TFBSs. DICE (downstream immunoglobulin control element), EVI1 (ecotropic virus integration site-1), GATA (family of transcriptional regulatory proteins), GREF (androgen receptor family), PCBE/PREB (prolactin regulatory element-binding protein), and RXRF (retinoid X receptor family). a Promoter structure without mutation effect. b Core promoter structure with new transcription binding sites created due to SNP rs41651668 T > C. c DNA sequences recognized by transcription factor families surrounding the second transcription start site (TSS-2). Nucleotides in red color denote the mutation site. Nucleotides in capitals denote the core sequence used by MatInspector (modified output of Genomatix-MatInspector software)