Expression of neuritin during liver maturation and regeneration.
Cell surface molecules are not only important for cell-cell interactions but also useful for a marker to define cell types and differentiation stages. Unlike hematopoietic system in which numerous such antigens have been identified, only a few cell surface molecules have been used to define differentiation stage of hepatocytes. In order to identify such cell surface molecules, we performed DNA microarray analysis using mRNA from fetal hepatocytes in E12.5 and E17.5 mice and cDNAs encoding a membrane protein were selected. Northern blot analysis was employed to confirm the genes upregulated during maturation of fetal hepatocytes and neuritin, a GPI-anchored protein, was found as a membrane protein expressed in hepatocytes, but not in nonparenchymal cells. Its expression increased along with liver development and the maximum expression was achieved from the neonatal to adult stage. The neuritin protein was localized in sinusoidal lumen of hepatocytes in adult liver. Partial hepatectomy transiently downregulated the expression of neuritin. The expression of neuritin mRNA in C/EBPalpha deficient liver was reduced to about 50% of that of wild type mice. Thus, neuritin expression is well correlated to the maturation of hepatocytes and can be a useful tool to define the differentiation stage of hepatocytes.
Kojima
Nobuhiko
N
Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan. kojima@iis.u-tokyo.ac.jp
Shiojiri
Nobuyoshi
N
Sakai
Yasuyuki
Y
Miyajima
Atsushi
A
D000818:Animals; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism; D005333:Fetus / Q000033:anatomy & histology; D058851:GPI-Linked Proteins; D018507:Gene Expression Regulation, Developmental; D022781:Hepatocytes / Q000166:cytology / Q000502:physiology; D008099:Liver / Q000166:cytology / Q000254:growth & development* / Q000502:physiology; D008115:Liver Regeneration; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D014018:Tissue Distribution
D022763:CCAAT-Enhancer-Binding Protein-alpha; D058851:GPI-Linked Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; C484377:Nrn1 protein, mouse; C105161:Nrn1 protein, rat