Asrl belongs in tomato to a gene family and encodes an acid soluble highly charged 13 kDa protein. We have isolated genomic clones of four members of the family, termed Asrl-Asr4. Asrl transcripts and ASR1 protein were detected in most organs of irrigated plants, where highest levels were found in fruits. However, water-stress, salt-stress and treatment with ABA acid, transiently increased the basal levels of Asrl mRNA and ASR1 protein. Asrl levels were also increased during fruit development and decreased during leaf development and aging. In addition, high levels of Asrl expression were detected in stamen. Using anti-ASR1 antiserum, we localized this protein in cell nuclei in the chromatin fraction. Water soluble ASR1 protein was expressed in E. coli was purified to homogeneity on heparin-agarose column followed by ion-chelating chromatography. Using the purified protein we could demonstrate Zn2+ dependent DNA-binding activity. We suggest that the ASR1 protein plays a role in the signal transduction cascade involved in plant response to water-stress and salt-stress.