title: Promoter analysis of the rabbit POU5F1 gene and its expression in preimplantation stage embryos.
abstract: BACKGROUND
  The POU5F1 gene encodes the octamer-binding transcription factor-4 (Oct4). It is crucial in the regulation of pluripotency during embryonic development and widely used as molecular marker of embryonic stem cells (ESCs). The objective of this study was to identify and to analyse the promoter region of rabbit POU5F1 gene; furthermore to examine its expression pattern in preimplantation stage rabbit embryos.
  
  
  RESULTS
  The upstream region of rabbit POU5F1 was subcloned sequenced and four highly conserved promoter regions (CR1-4) were identified. The highest degree of similarity on sequence level was found among the conserved domains between rabbit and human. Among the enhancers the proximal enhancer region (PE-1A) exhibited the highest degree of homology (96.4%). Furthermore, the CR4 regulator domain containing the distal enhancer (DE-2A) was responsible for stem cell-specific expression. Also, BAC library screen revealed the existence of a processed pseudogene of rabbit POU5F1. The results of quantitative real-time PCR experiments showed that POU5F1 mRNA was abundantly present in oocytes and zygotes, but it was gradually reduced until the activation of the embryonic genome, thereafter a continuous increase in POU5F1 mRNA level was observed until blastocyst stage. By using the XYClone laser system the inner cell mass (ICM) and trophoblast portions of embryos were microdissected and examined separately and POU5F1 mRNA was detected in both cell types.
  
  
  CONCLUSIONS
  In this study we provide a comparative sequence analysis of the regulatory region of rabbit POU5F1 gene. Our data suggest that the POU5F1 gene is strictly regulated during early mammalian development. We proposed that the well conserved CR4 region containing the DE-2A enhancer is responsible for the highly conserved ESC specific gene expression. Notably, we are the first to report that the rabbit POU5F1 is not restricted to ICM cells only, but it is expressed in trophoblast cells as well. This information may be well applicable to investigate further the possible phylogenetic role and the regulation of POU5F1 gene.
authors.affiliation: Micromanipulation and Genetic Reprogramming Group, Agricultural Biotechnology Center, Szent-Györgyi A, u, 4, H-2100 Gödöllo, Hungary. kobolak@abc.hu
authors.forename: Julianna
authors.initials: J
authors.lastname: Kobolak
authors.forename: Katalin
authors.initials: K
authors.lastname: Kiss
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Polgar
authors.forename: Solomon
authors.initials: S
authors.lastname: Mamo
authors.forename: Claire
authors.initials: C
authors.lastname: Rogel-Gaillard
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Tancos
authors.forename: Istvan
authors.initials: I
authors.lastname: Bock
authors.forename: Arpad G
authors.initials: AG
authors.lastname: Baji
authors.forename: Krisztina
authors.initials: K
authors.lastname: Tar
authors.forename: Melinda K
authors.initials: MK
authors.lastname: Pirity
authors.forename: Andras
authors.initials: A
authors.lastname: Dinnyes
mesh_terms: D000818:Animals; D001483:Base Sequence; D001755:Blastocyst / Q000378:metabolism*; D047108:Embryonic Development; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008969:Molecular Sequence Data; D050814:Octamer Transcription Factor-3 / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011817:Rabbits / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid
chemical_list: D050814:Octamer Transcription Factor-3