Transcriptome profiling reveals transcriptional and alternative splicing regulation in the early embryonic development of hair follicles in the cashmere goat

Yanjun Zhang,Dong Chen,Yanhong Zhao,Rui Su,Yi Zhang,Erhan Hai,Lele Wang,Zhihong Liu,Fangzheng Shang,Jinquan Li,Zhen Li,Ruijun Wang,Zhihong Wu,Wenjing Han,Zhiying Wang,Yaxun Wei,Zhixin Wang

doi:10.1038/s41598-019-54315-7

Yanjun Zhang, Dong Chen + Show 15 more

Open Access

https://doi.org/10.1038/s41598-019-54315-7

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Journal: Scientific Reports	Publication Date: Nov 28, 2019
Citations: 12	License type: open-access

Affiliation: Inner Mongolia Agricultural University

Abstract

The undercoat fiber of the cashmere goat, from the secondary hair follicle (HF), possesses commercial value. However, very few studies have focused on the molecular details of primary and secondary HF initiation and development in goat embryos. In this study, skin samples at embryonic day 45, 55, and 65 (E45, E55, and E65) were collected and prepared for RNA sequencing (RNA-seq). We found that the HF probably initiated from E55 to E65 by analyzing the functional pathways of differentially expressed genes (DEGs). Most key genes in canonical signaling pathways, including WNT, TGF-β, FGF, Hedgehog, NOTCH, and other factors showed clear expression changes from E55 to E65. We, for the first time, explored alternative splicing (AS) alterations, which showed distinct patterns among these three stages. Functional pathways of AS-regulated genes showed connections to HF development. By comparing the published RNA-seq samples from the E60, E120, and newborn (NB) stages, we found the majority of WNT/β-catenin signaling genes were important in the initiation of HF development, while other factors including FOXN1, GATA3, and DLX3 may have a consistent influence on HF development. Our investigation supported the time points of embryonic HF initiation and identified genes that have potential functions of embryonic HF initiation and development. We further explored the potential regulatory roles of AS in HF initiation, which extended our knowledge about the molecular mechanisms of HF development.

Highlights

The undercoat fiber of the cashmere goat, from the secondary hair follicle (HF), possesses commercial value
The molecular mechanisms of primary hair follicles (PHF) initiation that occur at early stages in embryonic development, and the transcriptional gene expression and alternative splicing related to HF morphogenesis in cashmere goats, still remain to be elucidated
Previous studies on cashmere goat embryonic HF development showed by morphological observation that PHF initiated between E55 and E657

Summary

Introduction

The undercoat fiber of the cashmere goat, from the secondary hair follicle (HF), possesses commercial value. Previous studies in humans and mice demonstrated that several pathways like WNT/beta-catenin, TGF-beta/BMP, FGF, Hedgehog, NOTCH, and other factors (SOX9, LHX2, DLX3, GATA3, RUNX1, TP63, MSX2, FOXN1, NFATC1, and TBX1) play important roles in HF development[8] Among these studies on HFs, few have been carried out in cashmere goats, whose skin is comprised of two types of HF, and studies are lacking on the early stages of HF development[15,16]. The molecular mechanisms of PHF initiation that occur at early stages in embryonic development, and the transcriptional gene expression and alternative splicing related to HF morphogenesis in cashmere goats, still remain to be elucidated. We assayed the gene expression profiles at these initial stages of HF morphogenesis and explored the potential molecular mechanisms by which signaling cascades in embryonic skin epidermis regulate HF formation. We found that the AS profile was distinct among the three different embryonic stages, implying potential regulatory roles in HF development

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