Nucleoplasmin-mediated unfolding of chromatin involves the displacement of linker-associated chromatin proteins.
We have previously characterized the interaction of nucleoplasmin with core histones and studied the possible involvement of this chaperone molecule in transcription. Here we study the interaction of nucleoplasmin with chromatin. We show that highly phosphorylated Xenopus laevis egg nucleoplasmin can unfold sperm and somatic chromatin in a way that involves the removal of chromosomal proteins from linker DNA regions without a stable interaction with the nucleosome. The complexes between egg nucleoplasmin and both somatic and sperm-specific linker proteins have been hydrodynamically characterized using sedimentation equilibrium in the analytical ultracentrifuge. The results are discussed within the context of the possible implication of nucleoplasmin in processes such as transcription and replication licensing which take place after egg fertilization at the onset of development.
Ramos
Isbaal
I
Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada.
Prado
Adelina
A
Finn
Ron M
RM
Muga
Arturo
A
Ausió
Juan
J
D000818:Animals; D002645:Chickens; D002843:Chromatin / Q000737:chemistry* / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000378:metabolism; D004527:Egg Proteins / Q000737:chemistry / Q000378:metabolism; D004912:Erythrocytes / Q000737:chemistry / Q000378:metabolism; D005260:Female; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D008297:Male; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism; D009687:Nuclear Proteins / Q000737:chemistry* / Q000378:metabolism; D056489:Nucleoplasmins; D009707:Nucleosomes / Q000737:chemistry / Q000378:metabolism; D009865:Oocytes / Q000737:chemistry / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism; D017510:Protein Folding; D029867:Xenopus Proteins / Q000737:chemistry* / Q000378:metabolism; D014982:Xenopus laevis
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004527:Egg Proteins; D006657:Histones; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D056489:Nucleoplasmins; D009707:Nucleosomes; D010750:Phosphoproteins; D029867:Xenopus Proteins; C026588:sperm basic nuclear proteins