O. Shimada et al., DETECTION OF DEOXYRIBONUCLEASE-I ALONG THE SECRETORY PATHWAY IN PANETH CELLS OF HUMAN SMALL-INTESTINE, The Journal of histochemistry and cytochemistry, 46(7), 1998, pp. 833-840
The expression and distribution of deoxyribonuclease I (DNase I) in hu
man duodenum, jejunum and ileum were examined by DNase I activity assa
y and the reverse transcriptase-polymerase chain reaction (RT-PCR), im
munofluorescence, in situ hybridization, and immunocytochemical ultras
tructural analyses. High levels of DNase I were detected in the cytopl
asm of Paneth cells in human small intestine. A tissue homogenate frac
tion rich in Paneth cells showed strong DNase I-specific enzymatic act
ivity. Immunofluorescence analysis using several specific anti-human D
Nase I antibodies showed very strong immunoreactivity in the cytoplasm
of every Paneth cell. In situ hybridization demonstrated high levels
of DNase I mRNA in Paneth cells. Immunogold electron microscopy reveal
ed gold particles localized along the secretory pathway, with the exoc
rine secretory granules mostly labeled. Our findings strongly suggest
that Paneth cells synthesize and secrete DNase I into the intestinal l
umen.