| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
RESEARCH |
1 Centre de recherche en reproduction animale, and 2 Départment de sciences cliniques, Faculté de médecine vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada J2S 7C6
Correspondence should be addressed to L C Smith; Email: smithl{at}medvet.umontreal.ca
Abnormal placental development limits success in ruminant pregnancies derived from somatic cell nuclear transfer (SCNT), due to reduction in placentome number and consequently, maternal/fetal exchange. In the primary stages of an epithelial–chorial association, the maternal/fetal interface is characterized by progressive endometrial invasion by specialized trophoblast binucleate/giant cells (TGC). We hypothesized that dysfunctional placentation in SCNT pregnancies results from aberration in expression of genes known to be necessary for trophoblast proliferation (Mash2), differentiation (Hand1), and function (IFN-
and PAG-9). We, therefore, compared the expression of these factors in trophoblast from bovine embryos derived from artificial insemination (AI), in vitro fertilization (IVF), and SCNT prior to (day 17) and following (day 40 of gestation) implantation, as well as TGC densities and function. In preimplantation embryos, Mash2 mRNA was more abundant in SCNT embryos compared to AI, while Hand1 was highest in AI and IVF relative to SCNT embryos. IFN- mRNA abundance did not differ among groups. PAG-9 mRNA was undetectable in SCNT embryos, present in IVF embryos and highest in AI embryos. In postimplantation pregnancies, SCNT fetal cotyledons displayed higher Mash2 and Hand1 than AI and IVF tissues. Allelic expression of Mash2 was not different among the groups, which suggests that elevated mRNA expression was not due to altered imprinting status of Mash2. The day 40 SCNT cotyledons had the fewest number of TGC compared to IVF and AI controls. Thus, expression of genes critical to normal placental development is altered in SCNT bovine embryos, and this is expected to cause abnormal trophoblast differentiation and contribute to pregnancy loss.
This article has been cited by other articles:
 |
|
 |
|
  S. Bauersachs, S. E. Ulbrich, V. Zakhartchenko, M. Minten, M. Reichenbach, H.-D. Reichenbach, H. Blum, T. E. Spencer, and E. Wolf The endometrium responds differently to cloned versus fertilized embryos PNAS, April 7, 2009; 106(14): 5681 - 5686. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Palmieri, P. Loi, G. Ptak, and L.D. Salda REVIEW PAPER: A Review of the Pathology of Abnormal Placentae of Somatic Cell Nuclear Transfer Clone Pregnancies in Cattle, Sheep, and Mice Vet. Pathol., November 1, 2008; 45(6): 865 - 880. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Hirayama, K. Sawai, S. Moriyasu, M. Hirayama, Y. Goto, E. Kaneko, A. Miyamoto, K. Ushizawa, T. Takahashi, and A. Minamihashi Excess estrogen sulfoconjugation as the possible cause for a poor sign of parturition in pregnant cows carrying somatic cell clone fetuses Reproduction, November 1, 2008; 136(5): 639 - 647. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S L Rodriguez-Zas, K Schellander, and H A Lewin Biological interpretations of transcriptomic profiles in mammalian oocytes and embryos Reproduction, February 1, 2008; 135(2): 129 - 139. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Blomberg, K. Hashizume, and C. Viebahn Blastocyst elongation, trophoblastic differentiation, and embryonic pattern formation Reproduction, February 1, 2008; 135(2): 181 - 195. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. M. Rivera, P. Stein, J. R. Weaver, J. Mager, R. M. Schultz, and M. S. Bartolomei Manipulations of mouse embryos prior to implantation result in aberrant expression of imprinted genes on day 9.5 of development Hum. Mol. Genet., January 1, 2008; 17(1): 1 - 14. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
