Cystatin-B is expressed by neural stem cells and by differentiated neurons and astrocytes.
Mutation in the gene encoding cystatin-B (CSTB) has been shown to cause progressive myoclonus epilepsy. Mice with a gene deletion of CSTB exhibit increased apoptosis of specific neurons but the physiological role of CSTB in brain cells is not fully understood. In the present study, we have examined the expression of CSTB in neural stem cells (NSC) and in differentiating mature brain cells. The results show that CSTB is present in embryonic and adult NSC and in the neuroepithelium. CSTB was expressed by both neurons and glial cells differentiated from NSC and in hippocampal cultures. CSTB localized mainly to the nucleus in NSC and in neurons, whilst in astrocytes CSTB was also in the cytoplasm. Double labeling showed that CSTB was present in the lysosomes in glial cells. The results demonstrate a nuclear expression of CSTB in NSC and in neurons, suggesting novel function for this molecule.
Brännvall
Karin
K
Department of Neuroscience, Neurobiology, Uppsala University, Biomedical Centre, Box 587, S-751 23 Uppsala, Sweden.
Hjelm
Helena
H
Korhonen
Laura
L
Lahtinen
Ulla
U
Lehesjoki
Anna-Elina
AE
Lindholm
Dan
D
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D001483:Base Sequence; D002454:Cell Differentiation; D002478:Cells, Cultured; D055313:Cystatin B; D015891:Cystatins / Q000235:genetics* / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D051379:Mice; D009154:Mutation; D020191:Myoclonic Epilepsies, Progressive / Q000209:etiology / Q000235:genetics / Q000503:physiopathology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*
C524994:CSTB protein, human; C524992:Cstb protein, mouse; D015891:Cystatins; D018076:DNA, Complementary; D055313:Cystatin B