Differential gene expression during elongation in the preimplantation pig embryo

Summary: On day 12–13 of gestation, the preimplantation pig conceptus undergoes a dramatic morphologic change from an approximately 1‐cm sphere to a nearly 1‐m long thread. This transformation, referred to as elongation, occurs in just 12–24 h. Elongation is primarily the result of trophectodermal cell shape changes, as there is relatively little mitosis during this stage of development. Thus far, descriptions of elongation have been limited to histologic and immunofluorescent studies of cell morphology and gross biochemical evaluations. We hypothesized that the changes in trophectoderm morphology likely involves significant changes in gene expression. Therefore, we used RNA arbitrarily primed‐PCR (RAP‐PCR) to characterize potential differential gene expression by trophectodermal cells during pig conceptus elongation. We found that the porcine heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 was shown to be differentially expressed by trophectodermal cells during elongation. We suggest that regulated alternative splicing may contribute to the morphogenetic process of elongation. genesis 26:9–14, 2000. Published 2000 Wiley‐Liss, Inc.