Nuclear Transfer Arrest Embryos Show Massive Dysregulation of Genes Involved in Transcription Pathways.

Chunshen Long,Hanshuang Li,Yongchun Zuo,Xinru Li,Wuritu Yang

doi:10.3390/ijms22158187

Abstract

Somatic cell nuclear transfer (SCNT) technology can reprogram terminally differentiated cell nuclei into a totipotent state. However, the underlying molecular barriers of SCNT embryo development remain incompletely elucidated. Here, we observed that transcription-related pathways were incompletely activated in nuclear transfer arrest (NTA) embryos compared to normal SCNT embryos and in vivo fertilized (WT) embryos, which hinders the development of SCNT embryos. We further revealed the transcription pathway associated gene regulatory networks (GRNs) and found the aberrant transcription pathways can lead to the massive dysregulation of genes in NTA embryos. The predicted target genes of transcription pathways contain a series of crucial factors in WT embryos, which play an important role in catabolic process, pluripotency regulation, epigenetic modification and signal transduction. In NTA embryos, however, these genes were varying degrees of inhibition and show a defect in synergy. Overall, our research found that the incomplete activation of transcription pathways is another potential molecular barrier for SCNT embryos besides the incomplete reprogramming of epigenetic modifications, broadening the understanding of molecular mechanism of SCNT embryonic development.

Highlights

Somatic cell nuclear transfer (SCNT) technology can reprogram terminally differentiated cell nuclei into a totipotent state to realize the cloning of animals [1]
We collected data on three pathways related to transcription process from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database according to the functional classification information of the pathway
In order to explore the developmental defects of SCNT embryos from the perspective of transcription-related pathways activation, we compared the gene expression patterns of basal transcription factors (TFs), RNA polymerase and spliceosome between in vivo fertilized embryos (WT) and SCNT embryos (Figure 1A)

Summary

Introduction

Somatic cell nuclear transfer (SCNT) technology can reprogram terminally differentiated cell nuclei into a totipotent state to realize the cloning of animals [1]. There are still many technical obstacles in SCNT that cause SCNT embryos to have low cloning efficiency, extra-embryonic tissues and some abnormal phenomena after the birth of cloned animals [6,7]. 70% of SCNT embryos are arrested at early cleavage stages, especially from the one-cell to the two-cell stage [8,9], which greatly limits the application of SCNT technology. The development of low-input sequencing technology has enabled more accurate analysis of transcriptome and epigenetic dynamics during SCNT reprogramming at single-cell resolution, providing new clues for revealing and overcoming molecular defects in somatic reprogramming [9,10,11].

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Results

Conclusion