The nuclear localization signal (NLS) of PDX-1 is part of the homeodomain and represents a novel type of NLS

被引:52
作者
Hessabi, B [1 ]
Ziegler, P [1 ]
Schmidt, I [1 ]
Hessabi, C [1 ]
Walther, R [1 ]
机构
[1] Univ Greifswald, Sch Med, Dept Biochem, Greifswald, Germany
来源
EUROPEAN JOURNAL OF BIOCHEMISTRY | 1999年 / 263卷 / 01期
关键词
beta cell; homeodomain proteins; nuclear localization signal; nuclear transport; transcription factors;
D O I
10.1046/j.1432-1327.1999.00481.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The beta-cell homeodomain transcription factor PDX-1 has vital functions both in controlling the expression of pancreatic polypeptide hormones and in the development of the pancreas. The transactivating and DNA-binding properties of PDX-1 have been well characterized, but nuclear transport is still undefined. Here we show that PDX-1 bears a nuclear localization signal (NLS) that is part of helix 3 of the homeodomain. PDX-1 deletion mutants were tagged with enhanced green fluorescent protein (EGFP) and expressed in COS-7 cells. Subcellular localization of the respective PDX-1-EGFP fusion proteins was analyzed by direct fluorescence microscopy and Western immunoblotting using an anti-(GFP). As a result we were able to demonstrate that the homeodomain or helix 3 alone was sufficient and necessary for transport into the nucleus. Point mutations of basic amino acid residues within helix 3 led to identification of an NLS with six amino acids being crucial for nuclear transport of PDX-1. Because this NLS does not match known examples of NLSs, the PDX-1 NLS may represent a novel class of NLS.
引用
收藏
页码:170 / 177
页数:8
相关论文
共 48 条
[1]  
Ausubel F.M., 1992, SHORT PROTOCOLS MOL, V2nd
[2]  
CARRIERE C, 1995, CELL GROWTH DIFFER, V6, P1531
[3]   INSULIN GENE-EXPRESSION IN NONEXPRESSING CELLS APPEARS TO BE REGULATED BY MULTIPLE DISTINCT NEGATIVE-ACTING CONTROL ELEMENTS [J].
CORDLE, SR ;
WHELAN, J ;
HENDERSON, E ;
MASUOKA, H ;
WEIL, PA ;
STEIN, R .
MOLECULAR AND CELLULAR BIOLOGY, 1991, 11 (05) :2881-2886
[4]   NUCLEAR TARGETING SEQUENCES - A CONSENSUS [J].
DINGWALL, C ;
LASKEY, RA .
TRENDS IN BIOCHEMICAL SCIENCES, 1991, 16 (12) :478-481
[5]   CELL-SPECIFIC EXPRESSION OF THE RAT INSULIN GENE - EVIDENCE FOR ROLE OF 2 DISTINCT-5' FLANKING ELEMENTS [J].
EDLUND, T ;
WALKER, MD ;
BARR, PJ ;
RUTTER, WJ .
SCIENCE, 1985, 230 (4728) :912-916
[6]   HEPATOCYTE NUCLEAR FACTOR 1-ALPHA IS EXPRESSED IN A HAMSTER INSULINOMA LINE AND TRANSACTIVATES THE RAT INSULIN-I GENE [J].
EMENS, LA ;
LANDERS, DW ;
MOSS, LG .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1992, 89 (16) :7300-7304
[7]   EFFECT OF 5'-FLANKING SEQUENCE DELETIONS ON EXPRESSION OF THE HUMAN INSULIN GENE IN TRANSGENIC MICE [J].
FROMONTRACINE, M ;
BUCCHINI, D ;
MADSEN, O ;
DESBOIS, P ;
LINDE, S ;
NIELSEN, JH ;
SAULNIER, C ;
RIPOCHE, MA ;
JAMI, J ;
PICTET, R .
MOLECULAR ENDOCRINOLOGY, 1990, 4 (05) :669-677
[8]   HOMEODOMAIN PROTEINS [J].
GEHRING, WJ ;
AFFOLTER, M ;
BURGLIN, T .
ANNUAL REVIEW OF BIOCHEMISTRY, 1994, 63 :487-526
[9]   THE INSULIN GENE CONTAINS MULTIPLE TRANSCRIPTIONAL ELEMENTS THAT RESPOND TO GLUCOSE [J].
GERMAN, MS ;
WANG, JH .
MOLECULAR AND CELLULAR BIOLOGY, 1994, 14 (06) :4067-4075
[10]   2 RELATED HELIX-LOOP-HELIX PROTEINS PARTICIPATE IN SEPARATE CELL-SPECIFIC COMPLEXES THAT BIND THE INSULIN ENHANCER [J].
GERMAN, MS ;
BLANAR, MA ;
NELSON, C ;
MOSS, LG ;
RUTTER, WJ .
MOLECULAR ENDOCRINOLOGY, 1991, 5 (02) :292-299