[Role of STAT1 on the regulation the human hsp90 alpha gene expression].
OBJECTIVE
To investigate the role of STAT1 on the regulation of human hsp90 alpha gene expression.


METHODS
We first transfected Jurkat cells with the STAT1 expression construct and analyzed the expression of hsp90 alpha gene expression via quantitative RT-PCR system. Then we co-transfected the STAT1 expression construct and the CAT reporter gene driven by different length of 5' flanking sequence of hsp90 alpha gene. Western blot was carried out to detect the level of tyrosine phosphorylation in Jurkat cells with and without heat shock treatment (42 degrees C 1 h). By electrophoretic mobility shift assays (EMSA), we evaluated the DNA binding activity of a STAT1 responsible element located in the regulatory region of hsp90 alpha gene in Jurkat cell nuclear extracts.


RESULTS
The mRNA level of hsp90 alpha gene in Jurkat cells was decreased when transfected by STAT1 expression construct, over-expression of STAT1 down-regulates the expression of CAT reporter gene with the present of a distal fragment from -1756 to -1463 within the 5' flanking regulatory sequences of hsp90 alpha gene. The tyrosine phosphorylation of STAT1 was detectable in Jurkat cells and increased when subjected to heat shock. Electrophoretic mobility shift assays (EMSA) results showed that STAT1 could bind to its responsible element in the regulatory region of hsp90 alpha gene.


CONCLUSIONS
STAT1 could negatively regulate the human hsp90 alpha gene expression.
Chen
X S
XS
National Laboratory of Medical Molecular Biology, CAMS and PUMC, Beijing 100005, China.
Wu
N H
NH
Shen
Y F
YF
D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D005786:Gene Expression Regulation; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics*; D006801:Humans; D019169:Jurkat Cells; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050794:STAT1 Transcription Factor; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D014162:Transfection
D004268:DNA-Binding Proteins; D018841:HSP90 Heat-Shock Proteins; D012333:RNA, Messenger; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D015534:Trans-Activators