The hiatus between oocyte and embryonic gene transcription dictates a role for stored maternal factors in early mammalian development. Encoded by maternal-effect genes, these factors accumulate during oogenesis and enable the activation of the embryonic genome, the subsequent cleavage stages of embryogenesis and the initial establishment of embryonic cell lineages. Recent studies in mice have y...

We describe two different cell interactions that appear to be required for the proper development of a pair of bilaterally symmetrical cells in Caenorhabditis elegans called the intestinal valve cells. Previous experiments have shown that at the beginning of the 4-cell stage of embryogenesis, two sister blastomeres called ABa and ABp are equivalent in development potential. We show that cell in...

The mouse embryo is surprisingly resistant to loss of individual cyclins or cyclin-dependent kinases. In a recent issue of Developmental Cell, Berthet et al. (2006) describe collaboration of Cdk2 and Cdk4 in embryogenesis that is revealed only upon their simultaneous loss, resulting in inappropriate activation of the retinoblastoma protein and embryonic lethality.

present study was conducted to consider the effects of different concentrations of 2,4-d and ba on somatic embryogenesis induction, development and maturation of three strawberry cultivars (kurdistan, parose and camarosa). for this purpose, leaf blade, nodal, petiole, stamen and flower bud calli were cultured on murashige and skoog (ms) medium supplemented with 2, 4 dichlorophenoxyacetic acid (...