MOLECULAR-CLONING OF MATRIN F/G - A DNA-BINDING PROTEIN OF THE NUCLEAR MATRIX THAT CONTAINS PUTATIVE ZINC FINGER MOTIFS

We have isolated a 2.7-kilobase rat liver cDNA clone that contains the entire 544-amino acid coding sequence for matrin F/G. This protein has previously been localized to the internal, fibrogranular areas of the nuclear matrix and shown to bind to DNA on nitrocellulose blots. The predicted amino acid sequence from the coding region of this cDNA shows that this protein contains almost-equal-to 50% hydrophobic amino acids with secondary structure predictions suggesting a large percentage of beta-sheet regions. No significant homologies were found with any other known proteins, including the nuclear lamins. The predicted amino acid sequence was also searched for DNA binding motifs. Two putative zinc finger motifs were found. In addition, a 7-mer palindromic sequence (Ser-Ser-Thr-Asn-Thr-Ser-Ser) was discovered within one of these zinc ringer DNA binding regions. A possible regulatory role for this element is discussed.