Testillano P S, González-Melendi P, Ahmadian P, Risueño M C
Laboratory of Nuclear Organization during Plant Development, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
J Struct Biol. 1995 Mar-Apr;114(2):123-39. doi: 10.1006/jsbi.1995.1012.
Methylation-acetylation (MA) is an easy and reproducible ultrastructural cytochemical method which gives preferential contrast to nucleic acid containing structures. When performed en bloc before Lowicryl embedding it does not affect the main antigenic and chemical properties of the sample and is compatible with a large variety of modern immunogold methods permitting a better assignment of the labelling to the well-defined nuclear structures. DNA, RNA, and nuclear proteins, with different chemical nature, nuclear localization, and amount, can be immunolocalized on MA-treated samples. Ultrastructural in situ hybridization and other approaches for studying the functional regions of chromatin, the terminal deoxynucleotidyl transferase and the bromodeoxyuridine methods, are also compatible with the MA procedure. It can be also performed on ultrathin cryosections and Lowicryl sections. A much better visualization of the nuclear structures is obtained, enhancing the distinction between the nucleolar granular and dense fibrillar components. Moreover, the combination of the MA procedure with EDTA regressive staining gives preferential contrast to the RNA-rich structures. It is proposed as a useful approach which can be regularly used for in situ studies of the functional organization of the nucleus in both plant and animal cells.
甲基化-乙酰化（MA）是一种简便且可重复的超微结构细胞化学方法，它能使含核酸的结构产生优先反差。在Lowicryl包埋前整体进行该方法时，它不会影响样品的主要抗原和化学性质，并且与多种现代免疫金方法兼容，从而能更好地将标记定位到明确的核结构上。具有不同化学性质、核定位和含量的DNA、RNA及核蛋白，均可在经MA处理的样品上进行免疫定位。超微结构原位杂交以及其他用于研究染色质功能区域、末端脱氧核苷酸转移酶和溴脱氧尿苷方法，也都与MA程序兼容。该方法也可在超薄冷冻切片和Lowicryl切片上进行。通过该方法能更好地观察核结构，增强核仁颗粒成分和致密纤维成分之间的区分。此外，MA程序与EDTA递减染色相结合，能使富含RNA的结构产生优先反差。它被认为是一种有用的方法，可常规用于植物和动物细胞核功能组织的原位研究。
