Preimplantation Mouse Embryos Express a Heat-Stable Alkaline Phosphatase1

Abstract

The cell surface alkaline phosphatase (APase) of the preimplantation mouse embryo has been characterized in situ by inhibition studies and fluorescent histochemistry. The embryonic APase has also been compared in the inhibition studies to the APase expressed on mouse F9 teratocarcinoma cells and, in some instances, to the APase of mouse intestinal epithelial cells. The embryonic APase was active over the pH range of 6.0-10.0, with the optimal pH for full activity in the range of 8.5-10.0. The embryonic APase was remarkably heat stable with significant loss of activity detected only after a 1 h incubation at 90 degrees C. A variety of specific and nonspecific APase inhibitors were applied to embryos to determine the nature of the APase isozymes expressed on these cells. The embryonic APase was totally resistant to levamisole, tetramisole, bromotetramisole, and L-homoarginine. The embryonic APase was inhibited by L-phenylalanine in a concentration-dependent fashion and by sodium arsenate, sodium vanadate, ethylenediamine tetraacetic acid, and slightly by 1,10-phenanthroline. The inhibition profile of the mouse embryonic APase, therefore, resembles most closely that reported for human placental APase with respect to heat stability and that reported for mouse intestinal APase with respect to inhibitor sensitivity.

Stage‐specific expression of alkaline phosphatase during neural development in the mouse

“…Two-to 8-cell stage mouse embryos express the tissue-specific EAP isozyme gene while blastocysts coexpress the EAP and TNAP isozymes as previously reported (Lepire and Ziomek, 1989;Hahnel et al, 1990). TNAP is considered a ubiquitous protein in adult life.…”

Developmental Expression of Alkaline Phosphatase Genes; Reexpression in Germ Cell Tumours and in vitro Immortalized Germ Cells

“…This pattern of expression resembles that found for the human GCAP isozyme. Indeed, a histochemical study on early mouse embryos indicated that EAP has character istics similar to PLAP and GCAP, including a remarkable heat stability and cross-reactivity with anti-PLAP poly clonal antisera [34]. It seems reasonable to assume that EAP and GCAP may have similar functions in the testis.…”

Inhibitor Profiles of Alkaline Phosphatases in Bovine Preattachment Embryos and Adult Tissues

“…In other species, however, TNAP and the tissue-specific isozymes have different sensitivities to temperature and chemical inhibition by various l -form amino acids and levamisole. Both mouse and human TNAP are particularly sensitive to inhibition with levamisole and l -homoarginine, and are comparatively insensitive to l -phenylalanine (Harris 1989;Lepire and Ziomek 1989;Millan 1990). The tissue-specific isozymes are comparatively insensitive to levamisole and l -homoarginine and sensitive to l -phenylalanine inhibition (Harris 1989;Lepire and Ziomek 1989;Millan 1990).…”

“…Both mouse and human TNAP are particularly sensitive to inhibition with levamisole and l -homoarginine, and are comparatively insensitive to l -phenylalanine (Harris 1989;Lepire and Ziomek 1989;Millan 1990). The tissue-specific isozymes are comparatively insensitive to levamisole and l -homoarginine and sensitive to l -phenylalanine inhibition (Harris 1989;Lepire and Ziomek 1989;Millan 1990). The human and murine TNAPs are inactivated by temperatures less than 60C, whereas the tissue-specific isozymes typically withstand higher temperatures (up to 90C;Harris 1989;Lepire and Ziomek 1989).…”