title: Identification of genetic networks involved in the cell growth arrest and differentiation of a rat astrocyte cell line RCG-12.
abstract: The purpose of the present study is to establish and characterize a conditionally immortalized astrocyte cell line and to clarify the genetic networks responsible for the cell growth arrest and differentiation. A conditionally immortalized astrocyte cell line, RCG-12, was established by infecting primary cultured rat cortical glia cells with a temperature-sensitive simian virus 40 large T-antigen. At a permissive temperature of 33 degrees C, the large T-antigen was expressed and cells grew continuously. On the other hand, the down-regulation of T-antigen at a non-permissive temperature of 39 degrees C led to growth arrest and differentiation. The cells expressed astrocyte-expressed genes such as glial fibrillary acidic protein. Interestingly, the differentiated condition induced by the non-permissive temperature significantly elevated the expression levels of several astrocyte-expressed genes. To identify the detailed mechanisms by which non-permissive temperature-induced cell growth arrest and differentiation, we performed high-density oligonucleotide microarray analysis and found that 556 out of 15,923 probe sets were differentially expressed 2.0-fold. A computational gene network analysis revealed that a genetic network containing up-regulated genes such as RB, NOTCH1, and CDKN1A was associated with the cellular growth and proliferation, and that a genetic network containing down-regulated genes such as MYC, CCNB1, and IGF1 was associated with the cell cycle. The established cell line RCG-12 retains some characteristics of astrocytes and should provide an excellent model for studies of astrocyte biology. The present results will also provide a basis for understanding the detailed molecular mechanisms of the growth arrest and differentiation of astrocytes.
authors: Division of Molecular Genetics Research, Life Science Research Center, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan. takasaki@cts.u-toyama.ac.jp
authors: Ichiro
authors: I
authors: Takasaki
authors: Satoko
authors: S
authors: Takarada
authors: Mamoru
authors: M
authors: Fukuchi
authors: Makoto
authors: M
authors: Yasuda
authors: Masaaki
authors: M
authors: Tsuda
authors: Yoshiaki
authors: Y
authors: Tabuchi
mesh_terms: D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000378:metabolism; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism* / Q000502:physiology*; D002452:Cell Count; D002454:Cell Differentiation; D002461:Cell Line, Transformed; D049109:Cell Proliferation; D002472:Cell Transformation, Viral; D002540:Cerebral Cortex / Q000166:cytology; D019295:Computational Biology / Q000379:methods; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004622:Embryo, Mammalian; D005786:Gene Expression Regulation / Q000502:physiology*; D053263:Gene Regulatory Networks; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry; D008957:Models, Genetic; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013696:Temperature; D014162:Transfection
chemical_list: D000952:Antigens, Polyomavirus Transforming; C493958:Cdkn1a protein, rat; D050759:Cyclin-Dependent Kinase Inhibitor p21; D005904:Glial Fibrillary Acidic Protein