High-throughput screening identifies CHMP4A associated with hypoxia-inducible factor 1.
OBJECTIVE
Tumor hypoxia is a common phenomenon and hypoxia-inducible factor-1 is the transcription factor that is most closely associated with hypoxia. Hypoxia-inducible factor-1 is overexpressed in most solid tumors and plays a vital role in hypoxic acclimatization, energy metabolism, tumor angiogenesis, tumor invasion, and drug tolerance in cancer cells. We aimed to identify novel human genes associated with the stability and transcriptional activity of hypoxia-inducible factor-1.


METHODS
A cell-based dual luciferase reporter system based on a hypoxia responsive element luciferase reporter gene was constructed to screen 409 novel human genes cloned in our lab. Western blot analysis was used to examine the changes in the expression level of hypoxia-inducible factor-1 α, and RT-PCR analysis was used to detect the transcription level of adenylate kinase 3.


RESULTS
Our results demonstrated that chromatin-modifying protein 4A could significantly up-regulate the hypoxia responsive element luciferase activity under both normoxic and cobalt chloride-induced hypoxic environment in HeLa cells. Moreover, Chromatin-modifying protein 4A could increase the expression of hypoxia-inducible factor-1 α protein under normoxic condition, and enhance the transcription level of adenylate kinase 3, which is one of the target genes of hypoxia-inducible factor-1.


CONCLUSIONS
The functional screening platform therefore can be applied for the high-throughput screening of hypoxia-inducible factor-1-related genes, which would provide new insights into underlying molecular mechanisms that may regulate hypoxia in mammalian cells.
Shi
Taiping
T
Chinese National Human Genome Center, #3-707 North YongChang Road BDA, Beijing 100176, PR China. taiping_shi@yahoo.com.cn
Dong
Yunqiao
Y
Li
Jing
J
Gao
Peng
P
Fu
Dongxu
D
Ma
Dalong
D
D015153:Blotting, Western; D015687:Cell Hypoxia; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics* / Q000502:physiology; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006367:HeLa Cells; D057166:High-Throughput Screening Assays; D006801:Humans; D051793:Hypoxia-Inducible Factor 1 / Q000235:genetics* / Q000378:metabolism; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics* / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D015854:Up-Regulation
C481529:CHMP4A protein, human; D056827:Endosomal Sorting Complexes Required for Transport; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008156:Luciferases