Differential gene expression during elongation in the preimplantation pig embryo

On day 12-13 of gestation, the preimplantation pig conceptus undergoes a dr amatic morphologic change from an approximately l-cm sphere to a nearly l-m long thread. This transformation, referred to as elongation, occurs in jus t 12-24 h. Elongation is primarily the result of trophectodermal cell shape changes, as there is relatively little mitosis during this stage of develo pment. Thus far, descriptions of elongation have been limited to histologic and immunofluorescent studies of cell morphology and gross biochemical eva luations. We hypothesized that the changes in trophectoderm morphology like ly involves significant changes in gene expression, Therefore, we used RNA arbitrarily primed-PCR (RAP-PCR) to characterize potential differential gen e expression by trophectodermal cells during pig conceptus elongation. We f ound that the porcine heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 was shown to be differentially expressed by trophectodermal cells during e longation, We suggest that regulated alternative splicing may contribute to the morphogenetic process of elongation. Published 2000 Wiley-Liss, Inc.(d agger)