A number of non-invasive methods have been proposed to evaluate embryo viability in human in-vitro fertilization programmes. In addition to biochemical analyses, a common method for the selection of embryos prior to transfer involves assessment of embryo quality and morphology. We propose a new method to evaluate embryo viability based on the timing of the first cell division. Fertilized embryo...

For many members of the Picornaviridae family, infection of cells results in a shutoff of host protein synthesis. For rhinoviruses and enteroviruses, the shutoff has been explained in part by the cleavage of eukaryotic initiation factor 4GI (eIF4GI), a component of the cap-binding protein complex eIF4F. The cleavage of eIF4GI is mediated by the virus-specific proteinase 2Apro and results in inh...

ICAM-1, a membrane-bound receptor, is released as soluble ICAM-1 in inflammatory diseases. To delineate mechanisms regulating ICAM-1 cleavage, studies were performed in endothelial cells (EC), human embryonic kidney (HEK)-293 cells transfected with wild-type (WT) ICAM-1, and ICAM-1 containing single tyrosine-to-alanine substitutions (Y474A, Y476A, and Y485A) in the cytoplasmic region. Tyrosine ...

We examined the effects of mitomycin C and aminopterin on ovulation in vivo and, fertilization, subsequent cleavage and implantation in slc-ICR female mice using methods of fertilization and culture in vitro. Chemicals were injected into mice at the MI (meiosis I) stage or 3 hours before the MI stage in order to examine their toxicity. Mitomycin C did not affect ovulation, but decreased the rat...

Rad21 is one of the major cohesin subunits that holds sister chromatids together until anaphase, when proteolytic cleavage by separase, a caspase-like enzyme, allows chromosomal separation. We show that cleavage of human Rad21 (hRad21) also occurs during apoptosis induced by diverse stimuli. Induction of apoptosis in multiple human cell lines results in the early (4 h after insult) generation o...

The regulation of apoptosis during infection is an important factor for host survival and, in some cases, also for the virus life cycle. At the same time, mechanisms to prevent the induction of apoptosis have been observed in numerous viral pathogens, but until now the role of apoptosis during arenavirus infection has not been investigated. Junin virus (JUNV) belongs to the New World arenavirus...

John Chant toward the bud orient the nucleus and spindle for mitosis Figure 1 illustrates the key point that, once a yeast cell has initiated a bud early in the cell cycle, it has Cambridge, Massachusetts 02138 committed to its cleavage plane. The molecular manifestation of commitment is the formation of a ring of septin proteins (Cdc3p, Cdc10p, Cdc11p, and Cdc12p) be-For one cell to divide int...

C3b was bound to human red cells when serum complement was activated by addition of antibodies directed against different red cell antigens, and the rate of cleavage to C3dg was determined by assay for loss of bound C3c antigens using radiolabeled monoclonal anti-C3c. When C3b was bound by antibodies to antigens on branched-chain glycoproteins, cleavage to C3dg occurred more rapidly than when C...

There is growing evidence that cell cleavage involves contraction in the region of the furrow and relaxation above the most distant parts of the spindle (see references 15 and 16) . The contractile mechanism has been likened to that of muscle, mainly as a result of studies of glycerinated models of dividing cells (7, 9) and extraction of an actomyosin-like material (8, 11) . Muscular contractio...

BACKGROUND Technology used for the purification of recombinant proteins is a key issue for the biochemical and structural analyses of proteins. In general, affinity tags, such as glutathione-S-transferase or six-histidines, are used to purify recombinant proteins. Since such affinity tags often interfere negatively with the structural and functional analyses of proteins, they are usually remove...