MFP1, a novel plant filament-like protein with affinity for matrix attachment region DNA.

Abstract

The interaction of chromatin with the nuclear matrix via matrix attachment regions (MARs) o n the DNA is considered to be of fundamental importance for higher order chromatin organization and regulation of gene expression. Here, we report a novel nuclear matrix-localized MAR DNA binding protein, designated MAR binding filament-like protein 1 (MFPl), from tomato. In contrast t o the few animal MAR DNA binding proteins thus far identified, MFPl contains a predicted N-terminal transmembrane domain and a long filament-like a-helical domain that is similar to diverse nuclear and cytoplasmic filament proteins from animals and yeast. DNA binding assays established that MFPl can discriminate between animal and plant MAR DNAs and non-MAR DNA fragments of similar size and AT content. Deletion mutants of MFPl revealed a novel, discrete DNA binding domain near the C terminus of the protein. MFPl is an in vitro substrate for casein kinase II, a nuctear matrix-associated protein kinase. Its structure, MAR DNA binding activity, and nuclear matrix localization suggest that MFP1 is likely to participate in nuclear architecture by connecting chromatin with the nuclear matrix and potentially with the nuclear envelope.

Evidence that Plasmodium falciparum chromosome end clusters are cross‐linked by protein and are the sites of both virulence gene silencing and activation

“…Slight dissociation of telomeric clusters is also seen when yeast nuclei are treated with TX-100 (Palladino et al, 1993b). There is little evidence for why this occurs, but one suggestion is because yeast lacks nuclear laminar networks that strongly tether higher order eukaryotic chromosomes to the nuclear envelope (Meier et al, 1996;Gindullis et al, 1999). Orthologues of lamins in P. falciparum are also not evident.…”

A member of the highly conserved FWL (tomato FW2.2-like) gene family is essential for soybean nodule organogenesis

“…A model was proposed whereby translocation of the b subunit from the cytosol to the nucleus leads to activation of the a subunit. CKII has been implicated in a wide variety of cellular functions, including control of cell division (Pepperkok et al, 1994;Espunya et al, 1999;Moreno-Romero et al, 2008), regulation of the signaling cascade leading to DNA repair after UV damage (Krohn et al, 2003), degradation of transcription factors and histone deacetylase 2 (Park et al, 2008;Adenuga et al, 2009), and interaction with high-mobility group proteins (Wisniewski et al, 1999;Krohn et al, 2003;Stemmer et al, 2003;Grasser et al, 2004), pea lamin-like proteins (Li and Roux, 1992) and MFP1 (MAR binding filament-like protein 1; Meier et al, 1996;Samaniego et al, 2006), a candidate protein involved in the attachment of chromatin to the nuclear matrix. Therefore, a finding that perturbations in the function of CKII lead to significant changes in nuclear size and chromatin structure would not be unexpected.…”

Two MAR DNA‐binding proteins of the pea nuclear matrix identify a new class of DNA‐binding proteins

“…1995). Tomato MFP1, which has no animal or insect homologues, is the only MAR‐binding protein that has been extensively characterized from plants (Meier et al. 1996).…”