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Educators' contributions to their institutions must be visible to be valued. The establishment of documentation standards for education activities provides the foundation for academic recognition of educators.

We have identified the beta (beta) isoform of the 14‐3‐3 family of proteins as an activator of the Raf‐1 protein kinase. 14‐3‐3 was isolated in a yeast two‐hybrid screen for Raf‐1 kinase domain binding proteins. Purified bovine brain 14‐3‐3 interacted specifically with both c‐Raf‐1 and the isolated Raf‐1 kinase domain. Association was sensitive to the activation status of Raf‐1; 14‐3‐3 bound to unactivated Raf‐1, but not Raf‐1 activated by protein kinase C alpha or Ras and Lck. The significance of these interactions under physiological conditions was demonstrated by co‐immunoprecipitation of Raf‐1 and 14‐3‐3 from extracts of quiescent, but not mitogen‐stimulated, NIH 3T3 cells. 14‐3‐3 was not a preferred Raf‐1 substrate in vitro and did not significantly affect Raf‐1 kinase activity in a purified system. However, in cell‐free extracts 14‐3‐3 acted as a Ras‐independent activator of both c‐Raf‐1 and the Raf‐1 kinase domain. The same results were obtained in vivo using transfection assays; 14‐3‐3 enhanced both c‐Raf‐1‐ and Raf‐1 kinase domain‐stimulated expression of AP‐1‐ and NF‐kappa B‐dependent reporter genes and accelerated Raf‐1 kinase domain‐triggered differentiation of PC12 cells. We conclude that 14‐3‐3 is a latent co‐activator bound to unactivated Raf‐1 in quiescent cells and mediates mitogen‐triggered but Ras‐independent regulatory effects aimed directly at the kinase domain.

A rapidly-labeled RNA fraction can be isolated from hen oviduct polysomes that has characteristics of the messenger RNA (mRNA) for the cell-specific protein, ovalbumin. This RNA, which sediments in the 8-17S region of sucrose gradients, possesses properties suggestive of the presence of a polyadenylic acid sequence and can be translated with fidelity in a cell-free protein synthesizing system derived from rabbit reticulocytes. The identity of the protein product as ovalbumin is confirmed by three methods, and translation of ovalbumin mRNA is shown to be dependent both on amount of exogenous mRNA and incubation time. Both rate and extent of ovalbumin synthesis is enhanced by the addition of a protein extract from ribosomes that contains peptide chain initiation factors. Finally, the presence of this specific mRNA is shown to be estrogen-dependent: it is induced by estrogen administration to immature chicks, disappears upon cessation of estrogen treatment, and can be reinduced by a single injection of estrogen to chicks that have been pretreated with estrogen and then withdrawn from the hormone.The cell-specific synthesis of ovalbumin serves as a characteristic biochemical marker for the estrogen-dependent differentiation of the chick oviduct (1-3). Studies to date have shown that estrogen induces changes in the pattern of synthesis of nuclear RNA before appearance of ovalbumin in the tissue (3-5). These observations are consistent with a hormone-regulated expression of the ovalbumin gene. However, the only direct assessment of messenger RNA (mRNA) is the ability of an RNA fraction to support the de novo synthesis of a specific protein in an in vitro translation system. Recently, rabbit reticulocyte lysate has been used successfully for this purpose by several laboratories, including our own (6-8). We now report data demonstrating that an 8-17S fraction of RNA isolated from oviduct polysomes contains the mRNA for ovalbumin that can be translated with fidelity in the reticulocyte system. Synthesis of ovalbumin in vitro shows a linear dependence on the amount of exogenous mRNA and is stimulated by addition of translation factors required for initiation of protein synthesis. Finally, the presence of the ovalbumin mRNA will be demonstrated to be directly dependent upon the degree of estrogen stimulation of the oviduct. MATERIALS AND METHODSAnimals. Immature chicks used in this study were Rhode Island Reds and were 7-days old at the beginning of the experiments. Young laying hens (5-6 months) were either Rhode Island Red or White Leghorns. For hormone experiments, immature chicks received daily subcutaneous injections of diethylstilbestrol (5 mg) in sesame oil. Precise injection protocols are described in the text.Isolation of Polysomes. Polyribosomes were isolated from chick oviduct as described. Fractionation of isolated polysomes on sucrose gradient has also been described (9, 10). For experiments with rapidly labeled polysomal RNA, oviduct was incubated in Eagle's minimal medium (1 ml/g) that contained [3H]...

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