Histochemical discrimination of endogenous mammalian beta-galactosidase activity from that resulting from lac-Z gene expression

Citation
Dj. Weiss et al., Histochemical discrimination of endogenous mammalian beta-galactosidase activity from that resulting from lac-Z gene expression, HISTOCHEM J, 31(4), 1999, pp. 231-236
Citations number
23
Categorie Soggetti
Medical Research Diagnosis & Treatment
Journal title
HISTOCHEMICAL JOURNAL
ISSN journal
00182214 → ACNP
Volume
31
Issue
4
Year of publication
1999
Pages
231 - 236
Database
ISI
SICI code
0018-2214(199904)31:4<231:HDOEMB>2.0.ZU;2-5
Abstract
Minces of several organs from the transgenic mouse ROSA beta-gal 26 (ROSA-2 6), which robustly expresses bacterial lac-Z in most tissues, were exposed to 4-bromo, 5-chloro, 3-indoyl, beta-D-galactopyrosanide (X-gal) at pH rang ing from 7.5 to 9.5 to determine the optimal pH for in situ demonstration o f bacterial beta-galactosidase activity (neutral pH optimum) while minimizi ng detection of potentially confounding endogenous mammalian beta-galactosi dase (acidic pH optimum). Similar studies were performed with organ minces from C57BL/6 mice, Sprague-Dawley rats, New Zealand white rabbits, and maca ques to confirm the effect of pH on minimizing detection of endogenous mamm alian beta-galactosidase. In all organs evaluated; heart, liver, spleen, ki dney, brain, and skeletal muscle, endogenous beta-galactosidase activity wa s rarely detected following incubation at pH greater than 7.5. In contrast, bacterial beta-galactosidase activity in the ROSA-26 mice was strongly det ected in organ minces following incubation at pH 8.0-9.0. These findings ar e similar to previous observations we have made in lung minces and confirm that a simple alteration of a commonly used histochemical technique for det ecting in situ beta-galactosidase activity, raising the reaction buffer pH to weakly alkaline range, can reliably distinguish between endogenous activ ity and that resulting from exogenous bacterial gene expression.