UC San Diego

Abl tyrosine kinase is a ubiquitously expressed non-receptor tyrosine kinase that undergoes constant nucleocytoplasmic shuttling. In response to DNA damage, Abl localizes and is activated in the nucleus to stimulate intrinsic apoptosis. Whereas in response to growth factors, Abl localizes and is activated in the cytoplasm to regulate actin dynamics. Depending on the subcellular localization of where Abl is activated, Abl decides the fate of the cell, making its visualization both useful and vital. Here we show the optimal immunofluorescence method to detect Abl in mouse tissues. Using this method, we have observed that WT mouse testis tissues express nuclear Abl in spermatid heads without DNA-damaging agents. We have also found that cisplatin treatments induce nuclear localization of Abl in Abl-WT mouse spleen and testis tissues, but not in Abl- μNLS mouse spleen and testis tissues. Due to the heterogeneity of cells expressing nuclear Abl in response to DNA damage, we hypothesized that Abl accumulates in the nucleus only in proliferating cells in response to DNA damage. So far, we have found that in response to DNA damage, Abl accumulates in the nucleus only in proliferating 3T3 WT cells.