Expression profiles of oviductal mRNAs and lncRNAs in the follicular phase and luteal phase of sheep (Ovis aries) with two fecundity gene (FecB) genotypes

FecB (also known as BMPR1B) is a crucial gene in sheep reproduction, which has a mutation (A746G) that was found to increase the ovulation rate and litter size. The FecB mutation is associated with reproductive endocrinology, such mutation can control external estrous characteristics and affect follicle-stimulating hormone during the estrous cycle. Previous researches showed that the FecB mutation can regulate the transcriptomic profiles in the reproductive-related tissues including hypothalamus, pituitary, and ovary during the estrous cycle of Small Tailed Han sheep (STH). However, little research has been reported on the correlation between FecB mutation and the estrous cycle in STH sheep oviduct. To investigate the coding and non-coding transcriptomic profiles involved in the estrous cycle and FecB in the sheep oviduct, RNA sequencing was performed to analyze the transcriptomic profiles of mRNAs and long non-coding RNAs (lncRNAs) in the oviduct during the estrous cycle of STH sheep with mutant (FecBBB) and wild-type (FecB++) genotypes. In total, 21,863 lncRNAs and 43,674 mRNAs were screened.Together, our results can provide novel insights into the oviductal transcriptomic function against a FecB mutation background in sheep reproduction. All experimental sheep and were kept in a sheltered outdoor paddock and were provided with alfalfa hay and concentrate, with clear water available ad libitum, the TaqMan probe was firstly applied to genotype the sheep population (n = 890). Then, six FecB ++ sheep and six FecB BB with no significant differences in age, weight, and body size (2.5±0.5 years old; weight 70±5 kg) were randomly selected from STH sheep with the FecB ++ genotype (n=142, wild type, w) and STH sheep with the FecB BB genotype (n=78, mutant type, M), respectively. All selected sheep were processed by estrous synchronization with Controlled Internal Drug Releasing Device (CIDR; progesterone 300 mg; Zoetis Australia Pty. Ltd., NSW, Australia) for 12 days. The six sheep, comprising three FecB ++ sheep and three FecB BB sheep, were euthanized within 45–48 h after CIDR removal (follicular phase) by administering a pentobarbital sodium overdose (1.5 mg/kg), the remaining six sheep were euthanized on day 9 after CIDR removal (luteal phase). Finally, the selected sheep were divided into four groups, including FecB ++ sheep in the follicular phase (wF), FecB ++ sheep in the luteal phase (wL), FecB BB sheep in the follicular phase (MF), and FecB BB sheep in the luteal phase (ML), based on their genotype record and estrous cycle. The oviduct isthmus tissues were collected for RNA-seq.