Bcl-2, Bax and Bcl-x expression in neuronal apoptosis: a study of mutant weaver and lurcher mice

We investigated the expression of the apoptosis modulating proteins Bcl-2, Bax and Bcl-x in the cerebellum of mutant lurcher and weaver mice. Lurcher Purkinje cells and weaver germinal (granule neuron progenitor) cells both die via apoptosis during the postnatal cerebellar development. No significant changes in the expression patterns were detected prior to the actual cell death process. Instead apoptotic lurcher Purkinje cells exhibited increased Bax and Bcl-x expression, while surviving cells had an expression pattern similar to that of healthy littermates. Increased Bax expression was also found in apoptotic weaver germinal cells, while no change of Bcl-x expression was detected. Bcl-2 was expressed at low levels in cerebellar neurons and no loss of Bcl-2 was evident. The observed expression patterns of Bcl-2, Bax and Bcl-x protein in apoptotic lurcher and weaver neurons support the hypothesis that the execution of neuronal apoptosis involves increased expression of Bax, which could represent a general mechanism in diverse neurodegenerative processes.