PARENT SESSION
GENE REGULATION AND FUNCTION - A

Tuesday, August 3, 2004
10:30 AM–12:30 PM
Buchanan Courtyard

(384) CHANGES IN THE RELATIVE ABUNDANCE OF MESSENGER RNA IN BOVINE BLASTOCYST (DAY 7) AND ELONGATED (DAY 16) EMBRYOS DERIVED FROM NUCLEAR TRANSFER.

Sawai, Ken¹, Kageyama, Soichi¹, Moriyasu, Satoru¹, Hirayama, Hiroki¹, Minamihashi, Akira¹, Onoe, Sadao¹, ¹ Hokkaido Animal Research Center, Shintoku, Japan

ABSTRACT- The gene transcription is important factor in development of embryos and production of normal offsprings derived from nuclear transfer (NTR). The objectives of the study were to determine the abundance of gene transcripts in bovine NTR embryos and comparison of the value with in vivo-produced embryos. Five specific mRNAs (interferon-; IFN-, octamer-binding transcription factor; OCT-4, DNA methyltransferase-1; DNMT-1, glucose transporter-1; GLUT-1 and interleukin-6; IL-6) were selected. Bovine blastocyst (BC) embryos were obtained from NTR used fetal fibloblast cell or uterus of donor cows at day 7 after AI (Vivo). Some BC embryos were transferred to recipient cows, and then elongated (EL) embryos were collected by uterine flushing at day 16 after estrus. Total RNA in single embryos was reverse transcribed for PCR. Quantification of mRNA abundance was performed by real-time PCR. The expression of each mRNA was normalized to the abundance of GAPDH. Most embryos (80 − 100%) were with positive signals of IFN- and OCT-4. Transcript signals of DNMT-1 in BC-NTR, GLUT-1 in EL-NTR and IL-6 in BC-Vivo were detected with lower frequencies of 25, 40 and 67%, respectively. The relative abundances of DNMT-1 and IL-6 were not significantly different in origins and stages of embryos. The expression of IFN- in EL-Vivo (25.75±10.88) was higher (P<0.05) than BC embryos (NTR; 1.42±0.40, Vivo; 0.93±0.19). In contrast, IFN- in EL-NTR (15.69±5.27) was not significantly different compared with EL-Vivo and BC embryos. Transcript of OCT-4 were higher (P<0.01) in BC embryos (NTR; 133.69±29.39, Vivo; 166.41±29.07) than EL embryos (NTR; 0.56±0.26, Vivo; 3.74±2.13). The expression of GLUT-1 in EL embryos were significantly (P<0.05) lower than BC embryos. Our results indicate that distinct mRNA transcription levels were observed between BC and EL embryos, and suggest that there are differences in the gene expression among the bovine embryos derived from NTR and in vivo.

KEY WORDS: embryo, bovine, nuclear transfer, gene expression