DNase X is a glycosylphosphatidylinositol-anchored membrane enzyme that provides a barrier to endocytosis-mediated transfer of a foreign gene.
DNase X is the first mammalian DNase to be isolated that is homologous to DNase I. In this study, we have examined its function using a novel monoclonal antibody and showed it to be expressed on the cell surface as a glycosylphosphatidylinositolanchored membrane protein. High level expression was observed in human muscular tissues and in myotubes obtained in vitro from RD rhabdomyosarcoma cells. We observed that RD myotubes incorporated a foreign gene, lacZ, by endocytosis but that expression of the encoded coding product, beta-galactosidase, was strongly inhibited. Overexpression of DNase X inhibited endocytosis-mediated gene transfer, whereas knockdown of DNase X with small interfering RNA had the opposite effect. These results reveal that DNase X provides a cell surface barrier to endocytosis-mediated gene transfer.
Shiokawa
Daisuke
D
Department of Biochemistry, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
Matsushita
Tokiyoshi
T
Shika
Yukari
Y
Shimizu
Mamoru
M
Maeda
Masahiro
M
Tanuma
Sei-ichi
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation; D002460:Cell Line; D017931:DNA Primers; D003851:Deoxyribonucleases / Q000378:metabolism*; D004705:Endocytosis; D019084:Fluorescent Antibody Technique, Indirect; D018014:Gene Transfer Techniques; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D034622:RNA Interference
D017931:DNA Primers; D017261:Glycosylphosphatidylinositols; D003851:Deoxyribonucleases