Embryo

Developmental Expression of 2,489 Gene Clusters During Pig Embryogenesis: An EST Project

Abstract
Identification of mRNAs that are present at early stages of embryogenesis is critical for a better understanding of development. To this end, cDNA libraries were constructed from germinal vesicle stage oocytes, in vivo produced 4-cell and blastocyst stage embryos, and from in vitro produced 4-cell and blastocyst stage embryos. Randomly picked clones (10,848) were sequenced from the 3' end and those of sufficient quality (8,066, 74%) were clustered into groups of sequence similarity (>95% identity), resulting in 2,489 clusters. The sequence of the longest representative expressed sequence tag (EST) of each cluster was compared to GenBank and TIGR. Scores below 200 were considered unique, and 1,114 (44.8%) did not have a match in either database. Sequencing from the 5' end yielded 12 of 37 useful annotations suggesting that 1/3 of the 1,114 might be identifiable; still leaving over 700 unique EST. Virtual Northerns compared between the stages identified numerous genes where expression appears to change from the germinal vesicle oocyte to the 4-cell stage, from the 4-cell to blastocyst stage, and between in vitro and in vivo derived 4-cell and blastocyst stage embryos. This is the first large scale sequencing project on early pig embryogenesis and has resulted in the discovery of a large number of genes as well as possible stage specific expression. Since many of these ESTs appear to not be in the public databases, their addition will be useful for transcriptional profiling experiments conducted on early pig embryos.

Key words: Embryo • Early development • Gene regulation

This article has been cited by other articles:

				V. Duranthon, A. J Watson, and P. Lonergan Preimplantation embryo programming: transcription, epigenetics, and culture environment Reproduction, February 1, 2008; 135(2): 141 - 150. [Abstract] [Full Text] [PDF]

				M. Misirlioglu, G. P. Page, H. Sagirkaya, A. Kaya, J. J. Parrish, N. L. First, and E. Memili Dynamics of global transcriptome in bovine matured oocytes and preimplantation embryos PNAS, December 12, 2006; 103(50): 18905 - 18910. [Abstract] [Full Text] [PDF]

				C. H. Chen, E. C. Lin, W. T. K. Cheng, H. S. Sun, H. J. Mersmann, and S. T. Ding Abundantly expressed genes in pig adipose tissue: An expressed sequence tag approach J Anim Sci, October 1, 2006; 84(10): 2673 - 2683. [Abstract] [Full Text] [PDF]

				K.M. Whitworth, C. Agca, J.-G. Kim, R.V. Patel, G.K. Springer, N.J. Bivens, L.J. Forrester, N. Mathialagan, J.A. Green, and R.S. Prather Transcriptional Profiling of Pig Embryogenesis by Using a 15-K Member Unigene Set Specific for Pig Reproductive Tissues and Embryos Biol Reprod, June 1, 2005; 72(6): 1437 - 1451. [Abstract] [Full Text] [PDF]