PMID- 16941707
OWN - NLM
STAT- MEDLINE
DCOM- 20070124
LR  - 20081121
IS  - 1040-452X (Print)
IS  - 1040-452X (Linking)
VI  - 74
IP  - 1
DP  - 2007 Jan
TI  - Activation of ribosomal RNA genes in porcine embryos produced in vitro or by 
      somatic cell nuclear transfer.
PG  - 35-41
AB  - The onset of ribosomal RNA (rRNA) synthesis occurs during the second half of the 
      third cell cycle, that is, at the four-cell stage, in porcine embryos developed 
      in vivo. In the present study the onset of rRNA synthesis was investigated in 
      porcine embryos produced in vitro (IVP) or by somatic cell nuclear transfer 
      (SCNT) using fluorescence in situ hybridization (FISH) with an rDNA probe and 
      subsequent visualization of the nucleolar proteins by silver staining. In the 205 
      IVP embryos investigated, all two-cell embryos (n = 34) were categorized as 
      transcriptionally inactive. At the late four-cell stage (n = 45), 38% of the 
      embryos contained 1-3 nuclei with signs of rRNA transcription, indicating an 
      asynchronous transcription initiation. This pattern continued in the following 
      stages, as 78% (n = 47), 47% (n = 42) and 83% (n = 37) of the embryos revealed a 
      mixture of transcriptionally inactive and active cells at the eight-cell, 16-cell 
      and blastocyst stage, respectively. In the 143 SCNT embryos investigated, all 
      two-cell embryos (n = 34) and early four-cell embryos (n = 12) were also 
      transcriptionally inactive. At the late four-cell stage (n = 33) and at the 
      eight-cell stage (n = 24) there were equal proportions of transcriptionally 
      active and inactive embryos and essentially all embryos that developed to the 
      16-cell stage (n = 21) and further to the blastocyst stage (n = 19) contained 
      only transcriptionally active cells. In conclusion, porcine embryos produced in 
      vitro had an asynchronous pattern of rRNA transcription initiation when compared 
      to SCNT and in vivo developed porcine embryos.
FAU - Bjerregaard, Bolette
AU  - Bjerregaard B
AD  - Department of Animal and Veterinary Basic Sciences, The Royal Veterinary and 
      Agricultural University, Frederiksberg C, Denmark.
FAU - Pedersen, Hanne G
AU  - Pedersen HG
FAU - Jakobsen, Anne S
AU  - Jakobsen AS
FAU - Rickords, Lee F
AU  - Rickords LF
FAU - Lai, Liangxue
AU  - Lai L
FAU - Cheong, Hee-Tae
AU  - Cheong HT
FAU - Samuel, Melissa
AU  - Samuel M
FAU - Prather, Randall S
AU  - Prather RS
FAU - Strejcek, Frantisek
AU  - Strejcek F
FAU - Rasmussen, Zaida R
AU  - Rasmussen ZR
FAU - Laurincik, Jozef
AU  - Laurincik J
FAU - Niemann, Heiner
AU  - Niemann H
FAU - Maddox-Hyttel, Poul
AU  - Maddox-Hyttel P
FAU - Thomsen, Preben D
AU  - Thomsen PD
LA  - eng
GR  - RR13438/RR/NCRR NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Mol Reprod Dev
JT  - Molecular reproduction and development
JID - 8903333
RN  - 0 (RNA, Ribosomal)
SB  - IM
MH  - Animals
MH  - Embryo, Mammalian/chemistry/*metabolism
MH  - Embryonic Development
MH  - Fertilization in Vitro
MH  - Genes, rRNA/*genetics
MH  - *Nuclear Transfer Techniques
MH  - RNA, Ribosomal/analysis/*biosynthesis/genetics
MH  - Sus scrofa/*embryology/genetics
MH  - Transcription, Genetic
MH  - *Transcriptional Activation
EDAT- 2006/08/31 09:00
MHDA- 2007/01/25 09:00
CRDT- 2006/08/31 09:00
PHST- 2006/08/31 09:00 [pubmed]
PHST- 2007/01/25 09:00 [medline]
PHST- 2006/08/31 09:00 [entrez]
AID - 10.1002/mrd.20594 [doi]
PST - ppublish
SO  - Mol Reprod Dev. 2007 Jan;74(1):35-41. doi: 10.1002/mrd.20594.