Nuclear localization signals in the Xenopus FGF embryonic early response 1 protein

FEBS Letters

Gillespie, Laura L.¹  Post, Janine N.¹  Paterno, Gary D.¹ 

[1] Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, 300 Prince Phillip Drive, St. John's, NF, Canada

关键词: Fibroblast growth factor;    Nuclear localization;    Early response 1;    Green fluorescent protein;    cdc2;    Phosphorylation;    Xenopus;   

DOI  :  10.1016/S0014-5793(01)02653-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Xenopus early response 1 (XER1) is a fibroblast growth factor-inducible transcription factor whose developmentally regulated nuclear localization is thought to be important in the control of cell differentation during embryonic development [Luchman et al., Mech. Dev. 80 (1999) 111–114]. Analysis of the XER1 amino acid sequence revealed four regions which contain potential nuclear localization sequences (NLSs). Using mutant XER1 proteins and portions of XER1 fused to green fluorescent protein (GFP) transfected into NIH 3T3 cells, we have determined that only one of these, NLS4, located near the carboxy-terminus of XER1, is necessary and sufficient for targeting exclusively to the nucleus. Of the other three predicted NLS sequences, only NLS1, consisting of the sequence ¹³⁸RPRRCK¹⁴³ was shown to function as a cryptic, weak NLS. NLS4 contains a core region consisting of the sequence ⁴⁶³RPIKRQRMD⁴⁷¹ which is similar to the core NLS directing the human c-MYC protein to the nucleus. The core sequence is flanked by a predicted cdc2/protein kinase A phosphorylation motif, however mutation of the serine⁴⁷² to alanine or aspartic acid had no detectable effect on accumulation of GFP-XER1 fusion proteins in the nucleus, demonstrating that this putative phosphorylation site plays no role in regulating nuclear transport.

【 授权许可】

Unknown