Effects of c-Jun and a negative dominant mutation of c-Jun on differentiation and gene expression in lens epithelial cells.
We have used a retroviral vector (RCAS) to overexpress wild-type chicken c-Jun or a deletion mutant of chicken c-Jun (Jun delta 7) lacking the DNA binding region to investigate the possible role of c-Jun in lens epithelial cell proliferation and differentiation. Both constructs were efficiently expressed in primary cultures of embryonic chicken lens epithelial cells. Overexpression of c-Jun increased the rate of cell proliferation and greatly delayed the appearance of "lentoid bodies," structures which contain differentiated cells expressing fiber cell markers. Excess c-Jun expression also significantly decreased the level of beta A3/A1-crystallin mRNA, without affecting alpha A-crystallin mRNA. In contrast, the mutated protein, Jun delta 7, had no effect on proliferation or differentiation but markedly increased the level of alpha A-crystallin mRNA in proliferating cell cultures. These results suggest that c-Jun or Jun-related proteins may be negative regulators of alpha A- and beta A3/A1-crystallin genes in proliferating lens cells.
Rinaudo
J A
JA
Laboratory of Molecular and Developmental Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892-2730, USA.
Vacchiano
E
E
Zelenka
P S
PS
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics; D002645:Chickens; D004847:Epithelial Cells; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005799:Genes, Dominant; D016758:Genes, jun; D005822:Genetic Vectors; D007908:Lens, Crystalline / Q000166:cytology*; D008969:Molecular Sequence Data; D017354:Point Mutation; D012190:Retroviridae / Q000235:genetics