Identification of the gene coding for the Endo B murine cytokeratin and its methylated, stable inactive state in mouse nonepithelial cells.

The Endo B type-I keratin intermediate filament protein is first expressed at the 4- to 8-cell stage of mouse development. In the adult, its expression is restricted to a variety of simple epithelial cell types. To investigate the mechanisms responsible for the restricted expression of Endo B, the gene coding for Endo B has been identified from among the five different Endo B genes found in the mouse genome by Southern hybridization analysis and cloning all or part of four of the genes.

Intermediate filament protein synthesis in preimplantation murine embryos.

The synthesis of two extraembryonic endodermal cytoskeletal proteins (Endo B, Mr = 50,000; Endo A, Mr = 55,000) was detected by immunoprecipitation at the 4- to 8-cell stage of preimplantation mouse development. The first detectable synthesis of both proteins occurs at about the same time as the earliest allocation of cells to the trophectodermal lineage. Both Endo A and B were identified in the two-dimensional gel pattern of blastocyst cytoskeletal proteins prepared by nonionic detergent and high-salt extraction.

New globoseries glycosphingolipids in human teratocarcinoma reactive with the monoclonal antibody directed to a developmentally regulated antigen, stage-specific embryonic antigen 3.

Glycolipids in a cultured human teratocarcinoma cell line (2102Ep) were investigated. The major glycolipids in these cells are globoseries glycolipids having the following structures: (formula; see text) Synthesis of these structures by serial addition of galactose, fucose, and N-acetylneuraminic acid to globoside (Gb4) in this teratocarcinoma is obvious, although further elongation of Gb4 in human cells and tissues has not been previously found with the exception of the presence of a small quantity of Forssman glycolipid in some tissues in the human population (Fs+ group) and in some human cancers. The latter four glycolipids (b-e), with the common internal structure R leads to 3GalNAc beta 1 leads to 3Gal alpha 1 leads to 4R', were all reactive to a monoclonal antibody directed to the 4- to 8-cell stage of murine embryos, known as the stage-specific embryonic antigen 3 (SSEA-3 (Shevinsky, L.

Monoclonal antibody to murine embryos defines a stage-specific embryonic antigen expressed on mouse embryos and human teratocarcinoma cells.

A murine stage-specific embryonic antigen (SSEA3) is defined by reactivity with a monoclonal antibody prepared by immunization of a rat with 4- to 8-cell-stage mouse embryos. This antigenic determinant, present on oocytes, becomes restricted first to the inner cell mass at the blastocyst stage, and later to the primitive endoderm. Murine teratocarcinoma stem cells do not react with this antibody, whereas human teratocarcinoma stem cells are SSEA3-positive.