Identification and characterization of a SET/NAP protein encoded by a brain-specific gene, MB20.
A new member of the NAP/SET gene family, named MB20, was isolated from a mouse brain cDNA library by virtue of its CAG trinucleotide repetitive sequence and a brain-specific gene expression pattern. The complementary DNA sequence predicted an open reading frame of 545 amino acids, with four copies of an 11-amino-acid direct repeat. The consensus sequence for these repeats, PKE-P--K-EE, is present in the largest subunit of murine neurofilament (NF-H). The MB20 protein sequence is homologous to nucleosome assembly proteins of several species, and its C-terminus is homologous to SET proteins. Immunoblot analysis revealed that MB20 protein is expressed in the brain. Transient transfection and immunofluorescence microscopy demonstrated that MB20 is distributed in the cytoplasm as well as in the nucleus. Deletion of the N-terminal end imparts the complete localization of MB20 protein to the nucleus. The ability of MB20 to bind histone proteins was analyzed by sucrose gradient sedimentation and by retention of histone proteins by immobilized MB20 protein. On the basis of its expression pattern, predicted sequence, and protein properties, we propose that MB20 plays a unique role in modulating nucleosome structure and gene expression during brain development.
Shen
H H
HH
Institute of Genetics, National Yang Ming University, Taipei, 112, Republic of China.
Huang
A M
AM
Hoheisel
J
J
Tsai
S F
SF
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001921:Brain / Q000378:metabolism*; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D002846:Chromatography, Affinity; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins; D004330:Drosophila; D017353:Gene Deletion; D015723:Gene Library; D006367:HeLa Cells; D056488:Histone Chaperones; D006657:Histones / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D016366:Open Reading Frames; D000075223:Poly-ADP-Ribose Binding Proteins; D011506:Proteins / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D014162:Transfection; D018911:Trinucleotide Repeats
D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D056488:Histone Chaperones; D006657:Histones; C112325:NAP1L3 protein, human; C413383:NCAPD2 protein, human; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; C513473:SET protein, human; D014157:Transcription Factors