A secreted 80 x 10(3) Mr protein mediates sensing of cell density and the onset of development in Dictyostelium.
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CMF is a secreted ~80-kDa protein purified from conditioned medium that acts as an in vivo indicator of cell density in starved cells.
"CMF is a secreted factor that functions in vivo as an indicator of cell density in starved cells"
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Below a threshold CMF concentration cells fail to express early developmental genes; sufficient CMF enables entry into the multicellular stage.
"When present below a threshold concentration, cells do not initiate the expression of genes required for early development"
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CMF is required for competence to induce prestalk and prespore gene expression in response to cAMP.
"necessary for cells to obtain the developmental competence to induce prestalk and prespore gene expression in response to cAMP"