Nuclear pH gradient

1. J Cell Sci. 1996 Jan;109 ( Pt 1):257-62.

Nuclear pH gradient in mammalian cells revealed by laser microspectrofluorimetry.

Seksek O(1), Bolard J.

Author information:

(1)LPBC (UA CNRS 2056), Université Pierre et Marie Curie, Paris, France.

Intracellular pH has been measured by laser microspectrofluorimetry, using the

pH-sensitive dyes SNARF-1, SNARF-calcein and SNARF-1-dextran. By this technique

it was possible to accurately determine pH in volumes as small as 0.5 x 0.5 x 1

microns 3. The probes were loaded into the cells either by diffusion of their

acetoxymethylester derivatives (SNARF-1-AM, SNARF-calcein-AM) or by

microinjection (SNARF-1-dextran). When the five types of cells were studied in

RPMI medium, the nuclear pH was consistently found to be 0.3 to 0.5 units above

that of the cytosol. Although the presence of pores in the nuclear membrane has

been taken as evidence that free diffusion of ions and small molecules can occur

in and out the nucleus, we conclude that the nuclear membrane of these cells

presents a permeability barrier to H+. The pH gradient was not observed in cells

suspended in PBS.

PMID: 8834810  [PubMed - indexed for MEDLINE]