Functional dissection of XDppa2/4 structural domains in Xenopus development.
The maintenance of pluripotency in mammalian embryonic stem cells depends upon the expression of regulatory genes like Oct3/4 and Sox2. While homologues of these genes are also characterized in non-mammalian vertebrates, like birds, amphibians and fish, existence and function of developmental pluripotency associated genes (Dppa) in lower vertebrates have not yet been reported. Here we describe a Dppa2/4-like gene, XDppa2/4, in Xenopus. The protein contains a SAP domain and a conserved C-terminal region. Overexpression of XDppa2/4, murine Dppa2 or Dppa4 produces similar phenotypes (defects in blastopore closure), while injection of XDppa2/4 morpholino generates a loss of blastopore closure and neural fold formation. Embryos die up to tailbud stage. mDppa2 (but not mDppa4) rescues blastopore closure and neurulation defects caused by XDppaMO, but does not prevent subsequent death of embryos. Although XDppa2/4 exhibits a Dppa-like expression pattern and is indispensable for embryogenesis, analyses of various marker genes make its role as a pluripotency factor rather unlikely. Both the gain and loss of function effects until the end of neurulation are caused by the conserved C-terminal region but not by the SAP domain. The SAP domain is required for association of XDppa2/4 to chromatin and for embryonic survival at later stages of development suggesting epigenetic programming events.
Siegel
Doreen
D
Institute of Biochemistry, University of Ulm, Albert-Einstein-Allee 11, D-89081 Ulm, Germany.
Schuff
Maximilian
M
Oswald
Franz
F
Cao
Ying
Y
Knöchel
Walter
W
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D054262:Gastrulation / Q000502:physiology; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D017403:In Situ Hybridization; D007267:Injections; D051379:Mice; D008969:Molecular Sequence Data; D054261:Neurulation / Q000502:physiology; D010641:Phenotype; D039904:Pluripotent Stem Cells / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D013347:Subcellular Fractions / Q000378:metabolism; D014981:Xenopus / Q000196:embryology* / Q000235:genetics; D029867:Xenopus Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D029867:Xenopus Proteins