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Four differently chromatin‐associated maize HMG domain proteins modulate DNA structure and act as architectural elements in nucleoprotein complexes
Author(s) -
Ritt Christoph,
Grimm Rudi,
Fernández Silvia,
Alonso Juan C.,
Grasser Klaus D.
Publication year - 1998
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1998.00154.x
Subject(s) - chromatin , nucleoprotein , dna , biology , hmg box , microbiology and biotechnology , non histone protein , ethidium bromide , histone , dna supercoil , dna binding protein , genetics , biophysics , gene , dna replication , transcription factor
Summary In contrast to other eukaryotes which usually express two closely related HMG1‐like proteins, plant cells have multiple relatively variable proteins of this type. A systematic analysis of the DNA‐binding properties of four chromosomal HMG domain proteins from maize revealed that they bind linear DNA with similar affinity. HMGa, HMGc1/2 and HMGd specifically recognise diverse DNA structures such as DNA mini‐circles and supercoiled DNA. They induce DNA‐bending, and constrain negative superhelical turns in DNA. In the presence of DNA, the HMG domain proteins can self‐associate, whereas they are monomeric in solution. The maize HMG1‐like proteins have the ability to facilitate the formation of nucleoprotein structures to different extents, since they can efficiently replace a bacterial chromatin‐associated protein required for the site‐specific β‐mediated recombination. A variable function of the HMG1‐like proteins is indicated by their differential association with maize chromatin, as judged by their ‘extractability’ from chromatin with spermine and ethidium bromide. Collectively, these findings suggest that the various plant chromosomal HMG domain proteins could be adapted to act in different nucleoprotein structures in vivo .