The Organization and Expression of the Human Dihydrofolate Reductase Gene in Methotrexate-Resistant and Methotrexate-Sensitive Cell Lines
<p>The analysis of several derivatives of the human cell lines HeLa and VA<sub>2</sub>-B, selected for resistance to methotrexate (MTX), shows a striking variability in the dihydrofolate reductase (DHFR) enzyme levels, chromosome constitution and growth characteristics in the absen...