In order to clarify whether the low Dnase1 activity in the kidney homogenates from B/W mice with membranoproliferative nephritis was due to inhibition of enzyme activity or to an absolute reduction in renal Dnase1 protein amount, western blotting was performed on the same samples that were used for SDS-PAGE gel zymography (Figure 1D). This evidence concerns the gene DNASE1 and nephritis.