Intact structure of EGAM1 homeoproteins and basic amino acid residues in the common homeodomain of EGAM1 and EGAM1C contribute to their nuclear localization in mouse embryonic stem cells

BackgroundETCHbox genes are eutherian-specific homeobox genes expressed during preimplantation development at a time when the first cell lineage decisions are being made. The mouse has an unusual repertoire of ETCHbox genes with several gene families lost in evolution and the remaining two, Crxos and Obox, greatly divergent in sequence and number. Each has undergone duplication to give a double homeodomain Crxos locus and a large cluster of over 60 Obox loci. The gene content differences between species raise important questions about how evolution can tolerate loss of genes implicated in key developmental events.ResultsWe find that Crxos internal duplication occurred in the mouse lineage, while Obox duplication was stepwise, generating subgroups with distinct sequence and expression. Ectopic expression of three Obox genes and a Crxos transcript in primary mouse embryonic cells followed by transcriptome sequencing allowed investigation into their functional roles. We find distinct transcriptomic influences for different Obox subgroups and Crxos, including modulation of genes related to zygotic genome activation and preparation for blastocyst formation. Comparison with similar experiments performed using human homeobox genes reveals striking overlap between genes downstream of mouse Crxos and genes downstream of human ARGFX.ConclusionsMouse Crxos and human ARGFX homeobox genes are paralogous rather than orthologous, yet they have evolved to regulate a common set of genes. This suggests there was compensation of function alongside gene loss through co-option of a different locus. Functional compensation by non-orthologous genes with dissimilar sequences is unusual but may indicate underlying distributed robustness. Compensation may be driven by the strong evolutionary pressure for successful early embryo development.Electronic supplementary materialThe online version of this article (10.1186/s13227-018-0091-4) contains supplementary material, which is available to authorized users.

show abstract

“…2 c). The 3′ Crxos transcript has also been previously reported to encode sequences essential for nuclear localisation of the protein [ 21 ].…”

Section: Resultsmentioning

confidence: 99%

Mouse Obox and Crxos modulate preimplantation transcriptional profiles revealing similarity between paralogous mouse and human homeobox genes

Royall

Maeso

Dunwell

et al. 2018

EvoDevo

View full text Add to dashboard Cite

show abstract

“…Conversely, EGAM1N supported the maintenance of an undifferentiated state [3,5]. EGAM1 homeoproteins were localized to the nuclei of mouse ES cells [6], and homeodomains are known as a DNA-binding region [7]; therefore, we postulated that EGAM1 homeoproteins act as DNA-binding transcription factors.…”

Section: Introductionmentioning

confidence: 89%

“…Immunofluorescence microscopy was performed as reported previously [6,13]. In brief, primary (rabbit anti-FLAG IgG, 1:2,000, #F7425, Sigma) and secondary (fluorescein isothiocyanate (FITC)-labeled anti-rabbit IgG, 1:1,000, #A120-201F, BETHYL Laboratories, Montgomery, TX, USA) antibodies were diluted in 1% bovine serum albumin in phosphate-buffered saline.…”

Section: Immunofluorescence Microscopymentioning

confidence: 99%

Exogenous TPRX1 homeoprotein modulates the gene expression of lineage-specific transcription factors in human embryonal carcinoma cells

Mori

Sakuraoka

Suzuki

et al. 2018

Biotechnology & Biotechnological Equipment

Self Cite

View full text Add to dashboard Cite

We reported previously that EGAM1 homeoproteins (EGAM1 and EGAM1N), transcribed from the Crxos gene as splicing variants, are expressed in preimplantation mouse embryos and mouse embryonic stem (ES) cells. Exogenous expression of these proteins affects the maintenance of an undifferentiated state and the progression of differentiation in mouse ES cells. Human tetrapeptide-repeat homeobox 1 (TPRX1), a member of the eutherian totipotent cell homeobox (ETCHbox) genes, is an ortholog of Crxos. However, the roles of TPRX1 in the differentiation of human pluripotent cells are still unknown. Because the TPRX1 transcripts were undetectable in an undifferentiated state and during the progression of differentiation in wild-type human embryonal carcinoma NT2/D1 cells, it would be advantageous to clarify the relationship between the exogenous expression of TPRX1 and the induction of genes encoding lineage-specific transcription factors in pluripotent cells. The expression of GATA6 and FOXA2, crucial transcription factors for the formation of the primitive endoderm, was upregulated, whereas that of CDX2, a crucial transcription factor for the formation of the trophectoderm, was downregulated by enforced expression of TPRX1. Overall, we suggest that TPRX1 is capable of modulating the expression of lineage-specific transcription factors in pluripotent cells derived from humans.

show abstract

Exogenous expression of homeoprotein EGAM1N prevents in vitro cardiomyogenesis by impairing expression of T and Nkx2.5, but not Mef2c, in mouse embryonic stem cells

et al. 2016

View full text Add to dashboard Cite

Generation of multiple cell types from embryonic stem (ES) cells and induced pluripotent stem cells is crucial to provide materials for regenerative medicine. EGAM1N has been found in preimplantation mouse embryos and mouse ES cells as a functionally unclassified homeoprotein. Recently, we reported that expression of EGAM1N suppressed the in vitro differentiation of ES cells into progenitor cells that arise in early embryogenesis. To clarify the effect of EGAM1N on terminal differentiation, embryoid bodies (EBs) were prepared from ES cells expressing exogenous Egam1n. In EBs expressing Egam1n, cardiomyogenesis was inhibited by impairing the expression of crucial transcription factors Brachyury T and Nkx2.5 in the generation of mesoderm and cardiomyocytes, respectively. Expression levels of Mef2c, another crucial gene for cardiomyogenesis, were unaffected. Conversely, the expression levels of Gata6 and Plat, markers for the primitive endoderm lineage, and Cdx2, a marker for the trophectoderm lineage, were increased. These results suggested that certain cell populations in EBs expressing Egam1n preferentially differentiated to such cell lineages. Our results suggest that EGAM1N not only affects the generation of progenitor cells during early embryogenesis, but also the progression of terminal differentiation, such as cardiomyogenesis, in mouse ES cells.

show abstract

Intact structure of EGAM1 homeoproteins and basic amino acid residues in the common homeodomain of EGAM1 and EGAM1C contribute to their nuclear localization in mouse embryonic stem cells

Cited by 7 publications

References 26 publications

Mouse Obox and Crxos modulate preimplantation transcriptional profiles revealing similarity between paralogous mouse and human homeobox genes

Mouse Obox and Crxos modulate preimplantation transcriptional profiles revealing similarity between paralogous mouse and human homeobox genes

Exogenous TPRX1 homeoprotein modulates the gene expression of lineage-specific transcription factors in human embryonal carcinoma cells

Exogenous expression of homeoprotein EGAM1N prevents in vitro cardiomyogenesis by impairing expression of T and Nkx2.5, but not Mef2c, in mouse embryonic stem cells

Contact Info

Product

Resources

About