title: Characterisation and high-resolution distribution of a matrix attachment region-binding protein (MFP1) in proliferating cells of onion.
abstract: The first matrix attachment region (MAR)-binding protein sequenced in plants, MFP1, has been characterised in two dicot species. Based on their antigenic relationship, we report here the conservation of MFP1-like proteins in proliferating root cells of onion (Allium cepa L). Two MFP1-like proteins with different molecular masses and solubilities were detected. The most abundant was a 90-kDa basic protein, presenting several separate spots in two-dimensional blots. The MFP1 was partially soluble and, similar to the proliferating cell nuclear antigen (PCNA)-labelled replication factories in the nucleus and nuclear matrix, was localised at discrete foci as detected by confocal microscopy. High-resolution immunolocalisation of MFP1 by electron microscopy identified the foci as nuclear structures, some of them containing PCNA, which are ultrastructurally similar to the replication factories described in animal cells. Our data provide the first report on MFP1-like proteins in the Alliaceae. In addition, we present evidence of the presence of AcMFP1 in the putative replication factories.
authors.affiliation: Department of Plant Biology, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Samaniego
authors.forename: W
authors.initials: W
authors.lastname: Yu
authors.forename: I
authors.initials: I
authors.lastname: Meier
authors.forename: S
authors.initials: S
authors.lastname: Moreno Díaz de la Espina
mesh_terms: D029681:Arabidopsis Proteins; D002467:Cell Nucleus; D004268:DNA-Binding Proteins / Q000378:metabolism*; D007150:Immunohistochemistry; D036961:Matrix Attachment Region Binding Proteins; D008565:Membrane Proteins / Q000378:metabolism*; D015530:Nuclear Matrix; D009687:Nuclear Proteins / Q000378:metabolism; D019697:Onions / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C120563:MAR binding filament-like protein 1, Arabidopsis; D036961:Matrix Attachment Region Binding Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins; D018809:Proliferating Cell Nuclear Antigen