Cloning and identification of genes that associate with mammalian replicative senescence.
Cellular senescence and limited proliferative capacity of normal diploid cells has a dominant phenotype over immortality of cancerous cells, suggesting its regulation by the expression of a set of genes. In order to isolate the genes that associate with senescence, we have employed a clonal system of conditional SV40 T antigen rat embryo fibroblast cell lines which undergo senescence upon T antigen inactivation. Construction of cDNA libraries from two conditional cell lines and application of differential screening and subtractive hybridization techniques have resulted in the cloning of eight senescence-induced genes (SGP-2/Apo J, alpha 1-procollagen, osteonectin, fibronectin, SM22, cytochrome C oxidase, GTP-alpha, and a novel gene) and a senescence-repressed gene (FRS-2). Three of these genes encode for extracellular matrix proteins, others are involved in the calcium-dependent signal transduction pathways, while the SGP-2/Apo J gene may have a cellular protective function. RNA analysis has shown that the senescence-associated genes are overexpressed in both normal rat embryonic fibroblasts and human osteoblasts cell cultures undergoing aging in vitro. In comparison, the expression of these genes in a rat fibroblast immortalized cell line (208F cells) was down-regulated after both its partial and its full transformation by ras oncogenes. Thus, cloning of senescence-associated genes opens up new ways to elucidate and/or to modulate aging and cancer.
Gonos
E S
ES
National Hellenic Research Foundation, Institute of Biological Research and Biotechnology, Athens, Greece. sgonos@eie.gr
Derventzi
A
A
Kveiborg
M
M
Agiostratidou
G
G
Kassem
M
M
Clark
B F
BF
Jat
P S
PS
Rattan
S I
SI
D000375:Aging / Q000235:genetics*; D000818:Animals; D002461:Cell Line, Transformed / Q000166:cytology / Q000502:physiology; D016922:Cellular Senescence / Q000235:genetics; D003001:Cloning, Molecular; D004261:DNA Replication / Q000235:genetics*; D018076:DNA, Complementary / Q000032:analysis; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D015723:Gene Library; D006023:Glycoproteins / Q000235:genetics; D006801:Humans; D008322:Mammals; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats
D018076:DNA, Complementary; D006023:Glycoproteins; D012333:RNA, Messenger