cDNA cloning of nuclear localization signal binding protein NBP60, a rat homologue of lamin B receptor, and identification of binding sites of human lamin B receptor for nuclear localization signals and chromatin.
We previously purified and characterized a nuclear localization signal (NLS) binding protein, NBP60, in rat liver nuclear envelopes. In this study, we cloned and sequenced the cDNA of rat NBP60, and predicted an amino acid sequence comprising 620 amino acids. The sequence revealed that NBP60 is a rat homologue of lamin B receptor (LBR), and is 79 and 63% identical in amino acids to human and chicken LBR, respectively. Using three fusion proteins containing different parts of the amino-terminal domain of human LBR, it was shown that the stretch comprising amino acids 1 to 89, which contains a Ser-Arg rich region (RS region), binds to nucleoplasmin and that the binding was inhibited by a common NLS-peptide. These results suggested that the amino-terminal domain of LBR contains an NLS-binding site. Furthermore, it was shown that the stretch comprising amino acids 1 to 53, which does not contain the RS region or the predicted DNA-binding site, binds to Xenopus laevis sperm chromatin.
Kawahire
S
S
Department of Biochemistry, Faculty of Science, Graduate School of Science and Technology, Niigata University, Igarashi.
Takeuchi
M
M
Gohshi
T
T
Sasagawa
S
S
Shimada
M
M
Takahashi
M
M
Abe
T K
TK
Ueda
T
T
Kuwano
R
R
Hikawa
A
A
Ichimura
T
T
Omata
S
S
Horigome
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002466:Cell Nucleolus / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics* / Q000302:isolation & purification; D015870:Gene Expression; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D010446:Peptide Fragments / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics*; D051381:Rats; D011916:Rats, Inbred F344; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D000097682:Lamin B Receptor
D002843:Chromatin; D018076:DNA, Complementary; D009687:Nuclear Proteins; D010446:Peptide Fragments; D010750:Phosphoproteins; D018160:Receptors, Cytoplasmic and Nuclear; D000097682:Lamin B Receptor; C075564:NOLC1 protein, human; C513067:Nolc1 protein, rat