[Transcription factor ZF5 regulates expression of mammalian gene containing GCC-triplet repeats in 5'-regulatory region in human hepatoma HepG2 cells].
Some nuclear proteins of human HeLa and HepG2 cells are capable of binding to GCC-triplet repeats--(GCC)n > 3 in 5'-regulatory regions of a number of mammalian genes--G-C-elements. According to our previous data, nucleotide sequence (GCC)4 in promoter of mouse ribosomal protein L32 gene (rpL32) between 17 and 6 bp upstream of transcription start site interacts to nuclear proteins from HepG2 cells, and may be considered as a GCC-element. We suggest that one of those proteins, with molecular weight about 52 kDa, which may interact with rpL32 GCC-element, is a known conservative mammalian transcription factor ZF5. DNA-binding domain of ZF5 contains a few Kruppel-like Zn-fingers (Cys2His2-type) interacting with the GC-rich nucleotide sequences in 5'-regulatory regions of a number of mammalian genes. Our results (obtained by EMSA) showed that recombinant GST-ZF5 fused protein containing ZF5 DNA-binding domain specifically binds a few GS-rich sequences: (GCC)g-9riplet repeats, 5'-GCGCGC-3' (known ZF5 consensus binding site) and (more preferable) the fragment (-24...+1 bp) of rpL32 promoter. The high affinity of ZF5 DNA-domain binding with the latter may be explained by the presence in this fragment of two overlapped subsequences, each being capable of binding to ZF5: (GCC)4 and 5'-GCGCGC- 3'. Zf5 cDNA was cloned from HepG2 cells by RT-PCR method, and then used for construction of the gene expression vector. It has been shown that Zf5 cDNA expression vector specifically down-regulates (in luciferase assays) the activity of rpL32 promoter (-155...+159) including the above mentioned GC-rich subsequences by cotransfection of HepG2 cells. Therefore, our results enable us to consider GCC-elements as a novel class of ZF5 targets in 5'-regulatory regions of mammalian genes.
Orlov
S V
SV
Kuteĭkin-Tepliakov
K B
KB
Grishin
A V
AV
Dizhe
E B
EB
Prokhorchuk
E B
EB
Perevozchikov
A P
AP
D045744:Cell Line, Tumor; D018076:DNA, Complementary; D004268:DNA-Binding Proteins / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D005809:Genes, Regulator; D006801:Humans; D051741:Kruppel-Like Transcription Factors; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D018911:Trinucleotide Repeats
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D051741:Kruppel-Like Transcription Factors; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C489978:ZBTB14 protein, human