# Transcriptomics Reveals the Differences in mRNA Expression Patterns in Yak Uterus of Follicular, Luteal, and Pregnant Phases

## TL;DR

This study uses transcriptomics to compare gene expression in yak uteruses during different reproductive phases, revealing key genes and pathways involved in reproduction.

## Contribution

The study identifies differentially expressed genes and their associated pathways in yak uteruses across follicular, luteal, and pregnant phases.

## Key findings

- 495 differentially expressed genes were identified between follicular and luteal phases, linked to adhesion, cell differentiation, and metabolism pathways.
- 1303 differentially expressed genes were found between luteal and pregnant phases, associated with multicellular processes and autophagy pathways.
- The findings offer insights into key biomarkers and regulatory mechanisms in yak reproduction.

## Abstract

Yaks are an important resource for the daily life of herders living in the Qinghai–Tibet Plateau. This study used RNA-seq technology to compare the mRNA expression patterns of the yak uterus during the follicular phase, the luteal phase, and the pregnant phase (n = 3/group). Numerous differentially expressed genes (DEGs) were obtained, and further enrichment analysis revealed that these DEGs were mainly associated with metabolism, adhesion, embryo implantation, and fetal growth and development. This study investigates the regulatory mechanisms of the yak uterus among different reproductive phases, providing theoretical references for further research on yak reproductive characteristics.

The yak, an important livestock mostly living in the Qinghai–Tibet Plateau region, has attracted massive attention due to its reproductive specificity. However, the molecular mechanism regulating yak uterine functions remains to be explored. This study utilized transcriptomics to identify differentially expressed genes (DEGs) in yaks across uteruses undergoing the follicular phase (UFP) (n = 3/group), luteal phase (ULP) (n = 3/group), and pregnant phase (UPP) (n = 3/group), aiming to depict and compare their transcriptomic characteristics. For the UFP and ULP groups, 495 DEGs were identified, including 329 upregulated and 166 downregulated DEGs in group ULP compared to UFP. Advanced analysis indicated that these DEGs between UFP and ULP were primary participants in GO items, such as adhesion, cell differentiation, and development, and were significantly enriched in KEGG signaling pathways like arachidonic acid metabolism, retinol metabolism, and cAMP signaling pathways. For the UFP and UPP groups, 353 DEGs were obtained, comprising 198 upregulated and 155 downregulated DEGs in group UPP compared to UFP. Advanced analysis showed that these DEGs between UFP and UPP were mainly related to GO items such as adhesion, binding, and the extracellular region, and were prominently enriched in KEGG signaling pathways like ECM-receptor interaction, the relaxing signaling pathway, and focal adhesion. For the groups ULP and UPP, 1303 DEGs were identified, encompassing 709 upregulated and 594 downregulated DEGs in group UPP compared to ULP. Advanced analysis indicated that these DEGs between ULP and UPP were associated with GO items such as multicellular organismal processes, cell differentiation, and the extracellular region, and mainly gathered in KEGG signaling pathways like signal transduction, cell differentiation, metabolism, and autophagy. These results provide valuable insights into the key biomarkers observable via dynamic changes in the yak uterus and offer a theoretical basis for further studies on yak reproductive mechanisms and improving production performance.