Identification and functional characterization of an alternative splice variant within the fourth exon of human nanog.
- Author:
Jung Sun KIM
1
;
Jiha KIM
;
Byung Soo KIM
;
Hee Yong CHUNG
;
Young Yiul LEE
;
Choon Sik PARK
;
Young Seek LEE
;
Young Han LEE
;
Il Yup CHUNG
Author Information
1. Division of Molecular and Life Sciences, College of Science and Technology, Hanyang University, Seoul 133-791, Korea. iychu@hanyang.ac.kr
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
alternative splicing;
totipotent stem cells;
GATA4 transcription factor;
hematopoietic stem cells;
NANOG protein human
- MeSH:
Alternative Splicing/*genetics;
Amino Acid Sequence;
Base Sequence;
Cell Nucleus;
Cells, Cultured;
DNA-Binding Proteins/chemistry/*genetics/metabolism;
Exons/*genetics;
GATA4 Transcription Factor/metabolism;
Gene Expression Profiling;
Genes, Reporter;
Homeodomain Proteins/chemistry/*genetics/metabolism;
Humans;
Introns/genetics;
Molecular Sequence Data;
Promoter Regions (Genetics);
RNA, Messenger/genetics/metabolism;
Research Support, Non-U.S. Gov't;
Trans-Activation (Genetics);
Transfection
- From:Experimental & Molecular Medicine
2005;37(6):601-607
- CountryRepublic of Korea
- Language:English
-
Abstract:
Nanog, a homeodomain (HD) transcription factor, plays a critical role in the maintenance of embryonic stem (ES) cell self-renewal. Here, we report the identification of an alternatively-spliced variant of nanog. This variant lacked a stretch of amino acids (residues 168-183) located between the HD and tryptophan-repeat (WR) of the previously-reported full length sequence, suggesting that the deleted sequence functions as a linker and possibly affects the flexibility of the C-terminal transactivation domain relative to the DNA binding domain. Expression of mRNA encoding the splice variant, designated as nanog-delta 48, was much lower than that of the full length version in human ES cells. The ratio of nanog-delta 48 transcript to full length transcript increased, however, in multipotent adult progenitor cells. EMSA analysis revealed that both forms of Nanog were able to bind a nanog binding sequence with roughly the same affinity. A reporter plasmid assay also showed that both variants of nanog modestly repressed transactivation of gata-4, whose expression is proposed to be inhibited by nanog, with comparable potency. We conclude that, despite the difference in primary structure and expression pattern in various stem cells, the alternatively-spliced variant of Nanog has similar activity to that of the full length version.
