Complex architecture and regulated expression of the Sox2ot locus during vertebrate development

  1. Paulo P. Amaral1,
  2. Christine Neyt1,
  3. Simon J. Wilkins1,
  4. Marjan E. Askarian-Amiri1,
  5. Susan M. Sunkin2,
  6. Andrew C. Perkins1 and
  7. John S. Mattick1
  1. 1ARC Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
  2. 2Allen Institute for Brain Science, Seattle, Washington 98103, USA

    Abstract

    The Sox2 gene is a key regulator of pluripotency embedded within an intron of a long noncoding RNA (ncRNA), termed Sox2 overlapping transcript (Sox2ot), which is transcribed in the same orientation. However, this ncRNA remains uncharacterized. Here we show that Sox2ot has multiple transcription start sites associated with genomic features that indicate regulated expression, including highly conserved elements (HCEs) and chromatin marks characteristic of gene promoters. To identify biological processes in which Sox2ot may be involved, we analyzed its expression in several developmental systems, compared to expression of Sox2. We show that Sox2ot is a stable transcript expressed in mouse embryonic stem cells, which, like Sox2, is down-regulated upon induction of embryoid body (EB) differentiation. However, in contrast to Sox2, Sox2ot is up-regulated during EB mesoderm-lineage differentiation. In adult mouse, Sox2ot isoforms were detected in tissues where Sox2 is expressed, as well as in different tissues, supporting independent regulation of expression of the ncRNA. Sox2dot, an isoform of Sox2ot transcribed from a distal HCE located >500 kb upstream of Sox2, was detected exclusively in the mouse brain, with enrichment in regions of adult neurogenesis. In addition, Sox2ot isoforms are transcribed from HCEs upstream of Sox2 in other vertebrates, including in several regions of the human brain. We also show that Sox2ot is dynamically regulated during chicken and zebrafish embryogenesis, consistently associated with central nervous system structures. These observations provide insight into the structure and regulation of the Sox2ot gene, and suggest conserved roles for Sox2ot orthologs during vertebrate development.

    Keywords

    Footnotes

    • Reprint requests to: John S. Mattick, ARC Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia; e-mail: j.mattick{at}imb.uq.edu.au; fax: 61-7-3346-2111.

    • Article published online ahead of print. Article and publication date are at http://www.rnajournal.org/cgi/doi/10.1261/rna.1705309.

      • Received April 24, 2009.
      • Accepted August 18, 2009.
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