Ps. Testillano et al., THE METHYLATION-ACETYLATION METHOD - AN ULTRASTRUCTURAL CYTOCHEMISTRYFOR NUCLEIC-ACIDS COMPATIBLE WITH IMMUNOGOLD STUDIES, Journal of structural biology, 114(2), 1995, pp. 123-139
Methylation-acetylation (MA) is an easy and re-producible ultrastructu
ral cytochemical method which gives preferential contrast to nucleic a
cid containing structures. When performed en bloc before Lowicryl embe
dding it does not affect the main antigenic and chemical properties of
the sample and is compatible with a large variety of modern immunogol
d methods permitting a better assignment of the labeling to the well-d
efined nuclear structures, DNA, RNA, and nuclear proteins, with differ
ent chemical nature, nuclear localization, and amount, can be immunolo
calized on MA-treated samples, Ultrastructural in situ hybridization a
nd other approaches for studying the functional regions of chromatin,
the terminal deoxynucleotidyl transferase and the bromodeoxyuridine me
thods, are also compatible with the MA procedure, It can be also perfo
rmed on ultrathin cryosections and Lowicryl sections. A much better vi
sualization of the nuclear structures is obtained, enhancing the disti
nction between the nucleolar granular and dense fibrillar components.
Moreover, the combination of the MA procedure with EDTA regressive sta
ining gives preferential contrast to the RNA-rich structures, It is pr
oposed as a useful approach which can be regularly used for in situ st
udies of the functional organization of the nucleus in both plant and
animal cells. (C) 1995 Academic Press, Inc.