PURIFICATION AND CDNA CLONING OF MAIZE HMGD REVEAL A NOVEL PLANT CHROMOSOMAL HMG-BOX PROTEIN WITH SEQUENCE SIMILARITY TO HMGA

We have purified the chromosomal high mobility group (HMG) protein HMG d from maize suspension culture cells, determined the N-terminal amino acid (aa) sequence, and isolated the corresponding cDNA. Sequence ana lysis showed that the cDNA encoded a protein of 126 aa residues with a theoretical mass of 14 104 Da. The protein contains an HMG-box DNA-bi nding domain and a short acidic C-terminal tail. HMGd is in approx. 65 % of its residues identical to maize HMGa, whereas it is only approx. 46% identical to maize HMGc1/2. The differences to the previously repo rted HMG proteins in aa sequence, in overall charge and in protein siz e indicate that we have identified a third type of plant chromosomal H MG-box protein belonging to the HMG1 protein family. Immunoblot analys is with a HMGd antiserum reveals that HMGd is expressed in all tissues tested. (C) 1997 Elsevier Science B.V.