用琼脂集落培养法和[~3H]-TdR参入法结合检测琥珀酸雌三醇酯钠盐(E_3·SNa)腹腔注射后小鼠血清集落刺激因子(CSF)水平升高的规律,CSF的类型及E_3·SNa本身对骨髓细胞增殖的影响。结果表明,E_3·SNa后6 h CSF水平即达到较高...用琼脂集落培养法和[~3H]-TdR参入法结合检测琥珀酸雌三醇酯钠盐(E_3·SNa)腹腔注射后小鼠血清集落刺激因子(CSF)水平升高的规律,CSF的类型及E_3·SNa本身对骨髓细胞增殖的影响。结果表明,E_3·SNa后6 h CSF水平即达到较高水平,24 h达最高峰,30 d时仍维持于较高水平。CSF活性在0.14～28 mg E_3·SNa剂量范围内随剂量增大而增加。CSF类型主要是GM-CSF。E_3·SNa本身对骨髓细胞增殖未见直接刺激作用。从而认为,雌激素对造血的作用很可能部分是由CSF介导的。展开更多
Protein post-translational modification （PTM） by ubiquitination has been observed during many aspects of plant growth, development, and stress responses. The ubiquitin-proteasome system precisely regulates phytohorm...Protein post-translational modification （PTM） by ubiquitination has been observed during many aspects of plant growth, development, and stress responses. The ubiquitin-proteasome system precisely regulates phytohormone signaling by affecting protein activity, localization, assembly, and interaction ability. Absci- sic acid （ABA） is a major phytohormone, and plays important roles in plants under normal or stressed growth conditions. The ABA signaling pathway is composed of phosphatases, kinases, transcription fac- tors, and membrane ion channels. It has been reported that multiple ABA signaling transducers are sub- jected to the regulations by ubiquitination. In particular, recent studies have identified different types of E3 ligases that mediate ubiquitination of ABA receptors in different cell compartments. This review focuses on modulation of these components by monoubiquitination or polyubiquitination that occurs in the plasma membrane, endomembranes, and from the cytosol to the nucleus; this implies the existence of retrograde and trafficking processes that are regulated by ubiquitination in ABA signaling. A number of single-unit E3 ligases, components of multi-subunit E3 ligases, E2s, and specific subunits of the 26S proteasome involved in ABA signal regulation are discussed. Dissecting the precise functions of ubiquitination in the ABA pathway may help us understand key factors in the signaling of other phytohormones regulated by ubiqui- tination and other types of PTMs.展开更多
文摘Protein post-translational modification （PTM） by ubiquitination has been observed during many aspects of plant growth, development, and stress responses. The ubiquitin-proteasome system precisely regulates phytohormone signaling by affecting protein activity, localization, assembly, and interaction ability. Absci- sic acid （ABA） is a major phytohormone, and plays important roles in plants under normal or stressed growth conditions. The ABA signaling pathway is composed of phosphatases, kinases, transcription fac- tors, and membrane ion channels. It has been reported that multiple ABA signaling transducers are sub- jected to the regulations by ubiquitination. In particular, recent studies have identified different types of E3 ligases that mediate ubiquitination of ABA receptors in different cell compartments. This review focuses on modulation of these components by monoubiquitination or polyubiquitination that occurs in the plasma membrane, endomembranes, and from the cytosol to the nucleus; this implies the existence of retrograde and trafficking processes that are regulated by ubiquitination in ABA signaling. A number of single-unit E3 ligases, components of multi-subunit E3 ligases, E2s, and specific subunits of the 26S proteasome involved in ABA signal regulation are discussed. Dissecting the precise functions of ubiquitination in the ABA pathway may help us understand key factors in the signaling of other phytohormones regulated by ubiqui- tination and other types of PTMs.
