AN ABA-BINDING PROTEIN WITH NUCLEIC ACID-BINDING PROPERTY

Maize cDNA expression library was screened using the antibodies agains t ABA-binding proteins (ABBP). From 200 000 separated phage plaques, o nly one cDNA clone coding for a polypeptide was obtained. It shows 60% -65% homology to the genes of nucleic acid-binding proteins in mammali a. However, about 120 cDNA clones coding maize 17s rRNA were unexpecte dly obtained. In view of this, the ABBP purified by ABA affinity chrom atography and the antibodies derived from the purified ABBP were exami ned. It is found that rRNA is indeed present in the ABBP. In addition, the obtained antibodies could recognize RNA as well as ABBP. It is su ggested that the ABBP have nucleic acid-binding property and can form a complex with rRNA.