The ASR proteins, which are induced by abscisic acid (ABA), stress, and ripening, were first described in tomato. They are characterized as small, basic proteins with strong hydrophilicity as a result of high levels of His, Glu, and Lys. Subcellular fractionation experiments and immunodetection in tomato fruit chromatin fractions suggested that tomato ASRI is localized to the nucleus. This conclusion agrees with the fact that loblolly pine (火炬松) and melon ASR possess a putative nuclear targeting signal at the C terminus. Moreover, these nuclear basic proteins can bind DNA, as demonstrated by DNA gel blot and filter binding experiments for tomato ASR1. These data support the idea that ASRs resemble eukaryotic nonhistone chromosomal proteins (该短文引自：The Plant Cell, 15: 2165)
