Abstract
Coformycin resistance in Chinese hamster fibroblasts is associated with co-amplification of four unknown genes (i.e. W, X, Y1, Y2) presumably closely linked to the target gene, AMP deaminase (Debatisse et al, Mol. Cell Biol. 6: 1776, 1986). The recent cloning of rat AMP deaminase cDNA (Sabina et al, J. Biol. Chem. 262: 12397, 1987) has provided the opportunity to further analyze this presumed amplicon. In order to accomplish this goal a coformycin-resistant rat myocyte subline was established from the parental L6 cell line. One stably resistant clonal isolate (i.e. clone 17) exhibits a 7-fold increase in AMP deaminase gene sequences. Hybridization with the four hamster cDNA's for genes W, X, Y1, and Y2 indicates that all are co-amplified and over-expressed in clone 17. These results delineate the AMP deaminase amplicon in the rat and document its similarity to the hamster amplicon. Another clonal isolate (i.e. clone 18) exhibits increased abundance of AMP-D, W, X, and Y2 transcript, yet none of these genes are amplified. This clone, therefore, represents an example of transcriptional activation without gene amplification and establishes that non-target (i.e. W, X, Y2) as well as target (i.e. AMP-D) genes are subject to this phenomenon. Experiments are in progress to determine if transcriptional activation always precedes gene amplification and whether the pattern of transcriptional activation predicts those genes that will ultimately be amplified. Finally, developmental analysis of rat myocytes indicates regulated expression of some of these amplicon genes during myogenesis.
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Sabina, R. 130 CHARACTERIZATION OF THE AMP DEAMINASE AMPLICON IN COFORMYCIN-RESISTANT RAT MYOCYTES. Pediatr Res 24, 132 (1988). https://doi.org/10.1203/00006450-198807000-00154
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DOI: https://doi.org/10.1203/00006450-198807000-00154