Tong C G, Kendrick R E, Roux S J
Department of Botany, University of Texas, Austin 78713, USA.
Photochem Photobiol. 1996 Nov;64(5):863-6. doi: 10.1111/j.1751-1097.1996.tb01848.x.
As assayed by western blot analysis, red light induces the appearance of epitopes recognized by anti-phosphotyrosine antibodies in several pea nuclear proteins. The immunostaining is blocked by preadsorbing the antibodies with phosphotyrosine but not by preadsorbing them with phosphoserine or phosphothreonine. This light response is observed whether the red light irradiation is given to pea plumules or nuclei isolated from the plumules. The red-light-induced response seen in plumules is reversible by a subsequent far-red-light irradiation, indicating that the likely photoreceptor for this response may be phytochrome. By immunoblot analysis pea phytochrome A, but not phytochrome B, can be detected in proteins extracted from pea nuclear chromatin-matrix preparations. Phytochrome A and the protein bands immunostained by anti-phosphotyrosine antibodies can be solubilized from unirradiated pea chromatin by 0.3 M NaCl, but irradiating this preparation with red light does not induce the appearance of phosphotyrosine-like epitopes in any nuclear proteins. These results suggest that the association of phytochrome with purified pea nuclei is such that its conversion to the far-red light-absorbing form can induce a post-translational epitope change in nuclear proteins in vivo.
通过蛋白质免疫印迹分析检测，红光可诱导几种豌豆核蛋白中出现能被抗磷酸酪氨酸抗体识别的表位。用磷酸酪氨酸预吸附抗体可阻断免疫染色，但用磷酸丝氨酸或磷酸苏氨酸预吸附抗体则不能阻断。无论将红光照射豌豆幼芽还是从幼芽中分离出的细胞核，均可观察到这种光反应。幼芽中红光诱导的反应可被随后的远红光照射逆转，这表明该反应可能的光受体是光敏色素。通过免疫印迹分析，在从豌豆核染色质-基质制剂中提取的蛋白质中可检测到豌豆光敏色素A，而检测不到光敏色素B。光敏色素A和被抗磷酸酪氨酸抗体免疫染色的蛋白带可通过0.3M NaCl从未经照射的豌豆染色质中溶解出来，但用红光照射该制剂不会在任何核蛋白中诱导出类似磷酸酪氨酸的表位出现。这些结果表明，光敏色素与纯化的豌豆细胞核的结合方式是，其向吸收远红光形式的转化可在体内诱导核蛋白发生翻译后表位变化。
