ArticleBiology of reproduction2026
Pregnancy in type I interferon receptor (IFNAR2) knockout sheep challenges the accepted paradigm for pregnancy recognition in ruminants†.
Article in Biology of reproduction, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
2 citing papers in PubMed.
- Pregnancy establishment in cattle without embryonic interferon tau.Nature communications · 2026Article
- Pregnancy Outcomes Following Artificial Insemination and Embryo Transfer in Dairy Cows-Expectations vs. Reality.Reproduction in domestic animals = Zuchthygiene · 2026Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
7 authors.
Funding
Abstract
The effects of type I interferons, including interferon tau (IFNT), previously thought to be the signal for pregnancy recognition in ruminants, are mediated by the type I interferon receptor (IFNAR), a heterodimer comprised of IFNAR1 and IFNAR2. The genes encoding IFNAR were disrupted in fetal fibroblast cells using CRISPR/Cas9 and lambs were produced by somatic cell nuclear transfer (SCNT). Subsequently, a herd of IFNAR2+/- sheep was developed and used to produce IFNAR2-/- lambs. Functional knockout of IFNAR was confirmed by failure of fibroblast cell lines from IFNAR2-/- sheep to respond to interferon alpha or IFNT in a quantitative reverse-transcription polymerase chain reaction assay for interferon-stimulated gene expression. Wild-type cells respond robustly in this assay. Successful production of IFNAR2-/- lambs by SCNT demonstrated that the conceptus did not need to express IFNAR or respond to IFNT. Nevertheless, because the accepted paradigm suggested that IFNT was required for pregnancy recognition, we hypothesized that IFNAR2-/- ewes would be infertile. It was, therefore, surprising when two ~9-month-old IFNAR2-/- ewes bred to an IFNAR2+/- ram became pregnant and had normal pregnancies culminating in healthy lambs in May 2023. These pregnancies demonstrate that the IFNAR, and presumably IFNT, are not required for the establishment or normal progression of pregnancy. Since IFNAR-/- fetuses survive to term, and both IFNAR2-/- rams and ewes are fertile, unless there is another receptor for IFNT, which is unlikely, IFNT is not required for pregnancy recognition or the development of a healthy ruminant fetus.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.