Conservation of matrix attachment region-binding filament-like protein 1 among higher plants

The interaction of chromatin with the nuclear matrix via matrix attachment regions (MARs) on the DNA is considered to be of fundamental importance for higher-order chromatin organization and the regulation of gene expression. We have previously isolated a novel nuclear matrix-localized protein (MFP1 ) from tomato (Lycopersicon esculentum) that preferentially binds to MAR DN A. Tomato MFP1 has a predicted filament-protein-like structure and is assoc iated with the nuclear envelope via an N-terminal targeting domain. Based o n the antigenic relationship, we report here that MFP1 is conserved in a la rge number of dicot and monocot species. Several cDNAs were cloned from tob acco (Nicotiana tabacum) and shown to correspond to two tobacco MFP1 genes. Comparison of the primary and predicted secondary structures of MFP1 from tomato, tobacco, and Arabidopsis indicates a high degree of conservation of the N-terminal targeting domain, the overall putative coiled-coil structur e of the protein, and the C-terminal DNA-binding domain. In addition, we sh ow that tobacco MFP1 is regulated in an organ-specific and developmental fa shion, and that this regulation occurs at the level of transcription or RNA stability.