Architectural defects in pronuclei of XXXX nuclear transplant embryos.

@entity31330 @entity19 @entity1219 @entity36909 @entity854 @entity5707
Reprogramming somatic nuclear function by transplantation of nuclei into recipient oocytes is associated with a morphological @entity5707 of the somatic nucleus. Successful cloning of animals by nuclear transplantation (NT) demonstrates that reprogramming somatic cell function is possible. However, low pregnancy rates and high frequencies of @entity854 in animals born suggest that reprogramming is rarely complete. To address this issue, we tested the hypothesis that nuclear transplantation leads to nuclear @entity5707 . We report the identification of several markers of morphological @entity5707 , or lack thereof, of @entity19 cumulus cell nuclei after transplantation into oocytes. Notably, nuclear transplant @entity19 embryos exhibit nuclear assembly of the differentiated cell-specific A-type lamins at the one-cell stage, as a result of misregulation of @entity31330 gene expression. The transplanted nuclei also display enhanced concentration of the nuclear matrix-associated protein NuMA as a result of translation from maternal mRNA and de novo transcription. The @entity36909 ( @entity36909 ), a marker of the nuclear envelope-chromatin interface, is of somatic origin. Furthermore, greater resistance of @entity36909 and DNA to in situ extractions of one-cell stage NT embryos with non-ionic detergent, DNase, RNase and @entity1219 reflects an enhanced proportion of heterochromatin in these embryos. Passage through first embryonic mitosis does not rescue the defects detected in one-cell stage embryos. We propose that somatic nuclear reprogramming deficiencies by NT might emanate from, at least in part, failure to remodel the somatic nucleus morphologically into a functional embryonic nucleus.
