Adenosine dialdehyde resistant sub-strains of murine erythroleukemia cells

Adenosine dialdehyde (Adox) is a potent inhibitor of S-adenosylhomocysteine hydrolase (SAHase). Adox resistant sub-stains of murine erythroleukemia cells (MELC) were developed by culturing cells in increasing Adox concentrations. The resulting resistant sub-strains grow in 200 μM Adox which is toxic to parental MELC. The S-adenosylhomocysteine (SAH) concentration of resistant cells in Adox is much lower than the SAH concentration of parental cells cultured with the inhibitor. SAHase activity is higher in resistant cells and this activity remains sensitive to inhibition by Adox. If [3H]Adox is used to label SAHase in cell extracts, a clearly labeled peak results in resistant cells that is absent in the parental line when extracts are separated by HPLC gel filtration. This peak coelutes with SAHase activity. The resistant cell lines cope with increasing Adox concentrations by increasing SAHase concentrations, which is possibly the result of gene amplification. To obtain a gene probe for SAHase to use in quantifying the number of SAHase genes per cell, mouse liver SAHase has been purified and a portion will be sequenced leading to the construction of a DNA probe