Isolation, cloning, and expression of a new murine zinc finger encoding gene

In vivo genome-wide CRISPR screening identifies ZNF24 as a negative NF-κB modulator in lung cancer

Systemic identification of tumor suppressor genes (TSGs) and elucidation of their signaling provide a new angle for understanding of tumorigenesis, which is important for developing successful treatment for lung cancer patients. In our current work, we conducted an in vivo screen for lung cancer TSGs through CRISPR/Cas9 mediated knockout of genes at genome-wide scale. We found that ZNF24 was a potent and clinically relevant TSG of lung cancer. Ectopic expression of ZNF24 arrested lung cancer cells in S phase. Mechanistically, ZNF24 bound to promoter region of P65 to negatively regulate its transcription and thereby the signaling activity of NF-κB pathway. This signaling cascade is clinically relevant. Importantly, we found that combinational inhibition of KRAS, NF-κB, and PD-1 effectively shrank autochthonous Kras^G12D/ZNF24^-/- lung cancers in transgenic mouse model. Our current work thus revealed an important role played by loss of function of ZNF24 in lung tumorigenesis and shed new light in precision medicine for a portion of lung cancer patients.

ZNF24 is upregulated in prostate cancer and facilitates the epithelial-to-mesenchymal transition through the regulation of Twist1

Zinc finger protein 24 (ZNF24) has been demonstrated to regulate proliferation, differentiation and migration as well as invasion in several types of cells. However, the molecular role and clinical effects of ZNF24 in prostate cancer (PCa) remain unclear. The present study revealed that ZNF24 expression is upregulated in PCa, and associated with tumor volume, Gleason score, pathological grade and metastasis. Wound healing and Transwell invasion assays revealed that ectopic ZNF24 expression facilitated cell migration and invasion through the Twist1-induced epithelial-to-mesenchymal transition (EMT) process. In addition, colony formation and Cell Counting Kit-8 assays were used to determine the regulatory effects of ZNF24 on proliferation. The results suggested that ZNF24 also promoted cell proliferation in PCa. ZNF24 acted as an oncogene and promoted migration, invasion and EMT of PCa cells via the regulation of Twist1.

The endogenous zinc finger transcription factor, ZNF24, modulates the angiogenic potential of human microvascular endothelial cells

We have previously identified a zinc finger transcription factor, ZNF24 (zinc finger protein 24), as a novel inhibitor of tumor angiogenesis and have demonstrated that ZNF24 exerts this effect by repressing the transcription of VEGF in breast cancer cells. Here we focused on the role of ZNF24 in modulating the angiogenic potential of the endothelial compartment. Knockdown of ZNF24 by siRNA in human primary microvascular endothelial cells (ECs) led to significantly decreased cell migration and invasion compared with control siRNA. ZNF24 knockdown consistently led to significantly impaired VEGF receptor 2 (VEGFR2) signaling and decreased levels of matrix metalloproteinase-2 (MMP-2), with no effect on levels of major regulators of MMP-2 activity such as the tissue inhibitors of metalloproteinases and MMP-14. Moreover, silencing ZNF24 in these cells led to significantly decreased EC proliferation. Quantitative PCR array analyses identified multiple cell cycle regulators as potential ZNF24 downstream targets which may be responsible for the decreased proliferation in ECs. In vivo, knockdown of ZNF24 specifically in microvascular ECs led to significantly decreased formation of functional vascular networks. Taken together, these results demonstrate that ZNF24 plays an essential role in modulating the angiogenic potential of microvascular ECs by regulating the proliferation, migration, and invasion of these cells.

Zinc finger transcription factor 191, directly binding to β-catenin promoter, promotes cell proliferation of hepatocellular carcinoma

Activation of β-catenin, the central effector of the canonical wingless-type (Wnt) pathway, has been implicated in hepatocellular carcinoma (HCC). However, the transcription regulation mechanism of the β-catenin gene in HCC remains unknown. Here we report that human zinc finger protein 191 (ZNF191) is a potential regulator of β-catenin transcription. ZNF191, a Krüppel-like protein, specifically interacts with the TCAT motif, which constitutes the HUMTH01 microsatellite in the tyrosine hydroxylase (TH) gene ex vivo. We demonstrate that ZNF191 is significantly overexpressed in human HCC specimens and is associated with growth of human HCC cells. Global profiling of gene expression in ZNF191 knockdown human hepatic L02 cells revealed that the important Wnt signal pathway genes β-catenin and cyclin D1 messenger RNAs (mRNAs) are significantly down-regulated. In agreement with transcription level, β-catenin and cyclin D1 proteins are also down-regulated in transient and stable ZNF191 knockdown L02 and hepatoma Hep3B cell lines. Moreover, significant correlation between ZNF191 and β-catenin mRNA expression was detected in human HCCs. Promoter luciferase assay indicated that ZNF191 can increase transcription activity of the full-length β-catenin (CTNNB1) promoter, and nucleotide (nt)-1407/-907 of the CTNNB1 promoter exhibited the maximum transcriptional activity. Electrophoretic mobility shift assay showed that purified ZNF191 protein can directly bind to the CTNNB1 promoter, and the binding region is located at nt-1254/-1224. Finally, we demonstrate that the key binding sequence of ZNF191 in vivo is ATTAATT.

CONCLUSION

ZNF191 can directly bind to the CTNNB1 promoter and activate the expression of β-catenin and its downstream target genes such as cyclin D1 in hepatoma cell lines. This study uncovers a new molecular mechanism of transcription regulation of the β-catenin gene in HCC.

ZFP191 is required by oligodendrocytes for CNS myelination

The controlling factors that prompt mature oligodendrocytes to myelinate axons are largely undetermined. In this study, we used a forward genetics approach to identify a mutant mouse strain characterized by the absence of CNS myelin despite the presence of abundant numbers of late-stage, process-extending oligodendrocytes. Through linkage mapping and complementation testing, we identified the mutation as a single nucleotide insertion in the gene encoding zinc finger protein 191 (Zfp191), which is a widely expressed, nuclear-localized protein that belongs to a family whose members contain both DNA-binding zinc finger domains and protein-protein-interacting SCAN domains. Zfp191 mutants express an array of myelin-related genes at significantly reduced levels, and our in vitro and in vivo data indicate that mutant ZFP191 acts in a cell-autonomous fashion to disrupt oligodendrocyte function. Therefore, this study demonstrates that ZFP191 is required for the myelinating function of differentiated oligodendrocytes.

A transcript profiling approach reveals the zinc finger transcription factor ZNF191 is a pleiotropic factor

Background

The human zinc finger protein 191 (ZNF191) is a member of the SCAN domain family of Krüppel-like zinc finger transcription factors. ZNF191 shows 94% identity to its mouse homologue zinc finger protein 191(Zfp191), which is the most highly conserved among the human-mouse SCAN family member orthologues pairs. Zfp191 is widely expressed during early embryogenesis and in adult organs. Moreover, Zfp191^-/- embryos have been shown to be severely retarded in development and die approximately at embryonic day E7.5. ZNF191 can specifically interact with the widespread TCAT motif which constitutes the HUMTH01 microsatellite in the tyrosine hydroxylase (TH) gene. Allelic variations of HUMTH01 have been stated to have a quantitative silencing effect on TH gene expression and to correlate with quantitative and qualitative changes in the binding by ZNF191. In addition, ZNF191 displays a suppressive effect on the transcription; however, little downstream targets have identified.

Results

We searched for ZNF191 target genes by using a transient overexpression and knockdown strategy in the human embryo kidney (HEK293) cells. Microarray analyses identified 6094 genes modulated by overexpression of ZNF191 and 3332 genes regulated by knockdown of ZNF191, using a threshold of 1.2-fold. Several interested candidate genes, validated by real time RT-PCR, were correlated well with the array data. Interestingly, 1456 genes were identified in both transient overexpression and transient knockdown strategies. The GenMAPP and MappFinder software packages were further used for pathway analysis of these significantly altered genes. Several gene pathways were found to be involved in processes of the regulation of kinase activity, transcription, angiogenesis, brain development and response to DNA damage.

Conclusion

Our analysis reveals for the first time that ZNF191 is a pleiotropic factor that has a role in hematopoiesis, brain development and cancers.

The zinc finger transcription factor 191 is required for early embryonic development and cell proliferation

Human zinc finger protein 191 (ZNF191/ZNF24) was cloned and characterized as a SCAN family member, which shows 94% identity to its mouse homologue zinc finger protein 191 (Zfp191). ZNF191 can specifically interact with an intronic polymorphic TCAT repeat (HUMTH01) in the tyrosine hydroxylase (TH) gene. Allelic variations of HUMTH01 have been stated to have a quantitative silencing effect on TH gene expression and to correlate with quantitative and qualitative changes in the binding by ZNF191. Zfp191 is widely expressed during embryonic development and in multiple tissues and organs in adult. To investigate the functions of Zfp191 in vivo, we have used homologous recombination to generate mice that are deficient in Zfp191. Heterozygous Zfp191(+/-) mice are normal and fertile. Homozygous Zfp191(-/-) embryos are severely retarded in development and die at approximately 7.5 days post-fertilization. Unexpectedly, in Zfp191(-/-) and Zfp191(+/-) embryos, TH gene expression is not affected. Blastocyst outgrowth experiments and the RNA interference-mediated knockdown of ZNF191 in cultured cells revealed an essential role for Zfp191 in cell proliferation. In further agreement with this function, no viable Zfp191(-/-) cell lines were obtained by derivation of embryonic stem (ES) cells from blastocysts of Zfp191(+/-) intercrosses or by forced homogenotization of heterozygous ES cells at high concentrations of G418. These data show that Zfp191 is indispensable for early embryonic development and cell proliferation.

Establishment of transgenic mice carrying gene encoding human zinc finger protein 191

AIM: Human zinc finger protein 191 (ZNF191) was cloned and characterized as a Krüppel-like transcription factor, which might be relevant to many diseases such as liver cancer, neuropsychiatric and cardiovascular diseases. Although progress has been made recently, the biological function of ZNF191 remains largely unidentified. The aim of this study was to establish a ZNF 191 transgenic mouse model, which would promote the functional study of ZNF191.

METHODS: Transgene fragments were microinjected into fertilized eggs of mice. The manipulated embryos were transferred into the oviducts of pseudo-pregnant female mice. The offsprings were identified by PCR and Southern blot analysis. ZNF 191 gene expression was analyzed by RT-PCR. Transgenic founder mice were used to establish transgenic mouse lineages. The first generation (F1) and the second generation (F2) mice were identified by PCR analysis. Ten-week transgenic mice were used for pathological examination.

RESULTS: Four mice were identified as carrying copies of ZNF191 gene. The results of RT-PCR showed that ZNF 191 gene was expressed in the liver, testis and brain in one of the transgenic mouse lineages. Genetic analysis of transgenic mice demonstrated that ZNF 191 gene was integrated into the chromosome at a single site and could be transmitted stably. Pathological analysis showed that the expression of ZNF 191 did not cause obvious pathological changes in multiple tissues of transgenic mice.

CONCLUSION: ZNF 191 transgenic mouse model would facilitate the investigation of biological functions of ZNF191 in vivo.

ZNF232: structure and expression analysis of a novel human C(2)H(2) zinc finger gene, member of the SCAN/LeR domain subfamily

We have identified a novel zinc finger gene, ZNF232, mapped to human chromosome 17p12. The coding region of the gene is organized in three exons corresponding to a 417 amino acid long polypeptide containing a SCAN/LeR domain and five C(2)H(2)-type zinc fingers. ZNF232 is possibly a nuclear protein, as suggested by expression analysis of GFP/ZNF232 chimeric constructs. ZNF232 transcripts were detected in a wide collection of adult human tissues. The gene is possibly subjected to tissue-specific post-transcriptional regulation by means of alternative splicing.