Castigli E, Mancinelli L, Mariggiò M A, Gianfranceschi G L
Institute of Cell Biology, University of Perugia, Italy.
Am J Physiol. 1993 Nov;265(5 Pt 1):C1220-3. doi: 10.1152/ajpcell.1993.265.5.C1220.
Three synthetic peptides, pyro-Glu-Ala-Gly-Glu-Ser-Glu-Asp (Pep A), pyro-Glu-Ala-Gly-Glu-Glu-Glu-Ser-Asn (Pep B), and pyro-Glu-Asp-Asp-Ser-Asp-Glu-Glu-Asn (Pep C), bear sequences possibly belonging to components of a naturally occurring family of strongly related small acidic chromatin peptides involved in regulation of gene expression. In a crude nuclear fraction and in purified nuclei from PC-12 cells, Pep A and Pep B activate RNA synthesis, specifically acting on the RNA polymerase II transcription system. On the other hand, Pep C shows an inhibitory effect on RNA synthesis in purified nuclei but an activation in the crude nuclear fraction. Control experiments show that the serum thymic factor does not affect RNA synthesis in the crude nuclear fraction or in purified nuclei. A possible regulation by peptide phosphorylation via casein kinase II (more active in purified nuclei than in the crude nuclear fraction) is discussed.
三种合成肽，焦谷氨酸-丙氨酸-甘氨酸-谷氨酸-丝氨酸-谷氨酸-天冬氨酸（肽A）、焦谷氨酸-丙氨酸-甘氨酸-谷氨酸-谷氨酸-谷氨酸-丝氨酸-天冬酰胺（肽B）和焦谷氨酸-天冬氨酸-天冬氨酸-丝氨酸-天冬氨酸-谷氨酸-谷氨酸-天冬酰胺（肽C），其序列可能属于一个天然存在的、与基因表达调控有关的强相关小酸性染色质肽家族的组成部分。在PC-12细胞的粗核组分和纯化细胞核中，肽A和肽B激活RNA合成，特异性作用于RNA聚合酶II转录系统。另一方面，肽C在纯化细胞核中对RNA合成有抑制作用，但在粗核组分中则有激活作用。对照实验表明，血清胸腺因子不影响粗核组分或纯化细胞核中的RNA合成。文中讨论了通过酪蛋白激酶II（在纯化细胞核中比在粗核组分中更具活性）进行肽磷酸化的可能调控作用。
