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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2009-5-27
pubmed:abstractText
Although the differential expression of heat shcok proteins, Hsp90alpha and Hsp90beta was extensively studied in many kinds of cells, the post-transcriptional regulation of Hsp90 isoforms remains unclear. In control and GA-treated rat gliosarcoma cells, it has been reported that the translational efficiency of hsp90alpha is higher than hsp90beta. In this study, we present evidences identifying the roles for leaky scanning and 5'-UTR sequence in translational regulation of Hsp90beta. The result of in vitro transcription and translation (IVTT) experiment showed that hsp90alpha exhibited higher translation efficiency than hsp90beta. Sequence analysis revealed that there is an out-of-frame downstream AUG codon in hsp90beta gene. However, elimination of the downstream AUG by site-directly mutagenesis or introducing Kozak context sequence around the initiator AUG of hsp90beta open reading frame increased its translational efficiency, which indicated that leaky scanning might be a possible mechanism regulating hsp90beta. Furthermore, we also constructed a firefly luciferase reporter system to verify the effect of subsequent translation at the downstream out-of-frame AUG codon in 9L and A549 cells. Furthermore, it is believed that 5'-untranslated region (5'-UTR) also plays a significant role in translational control. We showed hsp90beta 5'-UTR gives rise to the reduction of the translation efficiency in IVTT experiment. Additionally, the reductive effect of hsp90beta 5'-UTR was further confirmed by luciferase reporter assay using truncated deletion analyses of 5'-UTR of hsp90beta. Our results support the hypothesis that ribosome leaky scanning mechanism and 5'-UTR sequence acts as negative regulators in hsp90beta mRNA.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1097-4644
pubmed:author
pubmed:copyrightInfo
(c) 2009 Wiley-Liss, Inc.
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
107
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
418-27
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Control mechanisms of differential translation of Hsp90 isoforms in 9L rat gliosarcoma cells.
pubmed:affiliation
Department of Life Science, Institute of Biotechnology, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't