scholarly journals The putative zinc finger of a caulimovirus is essential for infectivity but does not influence gene expression

1993 ◽  
Vol 74 (4) ◽  
pp. 775-780 ◽  
Author(s):  
H. B. Scholthof ◽  
F. C. Wu ◽  
J. M. Kiernan ◽  
R. J. Shepherd
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wanlu Liu ◽  
Javier Gallego-Bartolomé ◽  
Yuxing Zhou ◽  
Zhenhui Zhong ◽  
Ming Wang ◽  
...  

AbstractThe ability to target epigenetic marks like DNA methylation to specific loci is important in both basic research and in crop plant engineering. However, heritability of targeted DNA methylation, how it impacts gene expression, and which epigenetic features are required for proper establishment are mostly unknown. Here, we show that targeting the CG-specific methyltransferase M.SssI with an artificial zinc finger protein can establish heritable CG methylation and silencing of a targeted locus in Arabidopsis. In addition, we observe highly heritable widespread ectopic CG methylation mainly over euchromatic regions. This hypermethylation shows little effect on transcription while it triggers a mild but significant reduction in the accumulation of H2A.Z and H3K27me3. Moreover, ectopic methylation occurs preferentially at less open chromatin that lacks positive histone marks. These results outline general principles of the heritability and interaction of CG methylation with other epigenomic features that should help guide future efforts to engineer epigenomes.


Development ◽  
1992 ◽  
Vol 116 (4) ◽  
pp. 943-952 ◽  
Author(s):  
X. Cui ◽  
C.Q. Doe

Cell diversity in the Drosophila central nervous system (CNS) is primarily generated by the invariant lineage of neural precursors called neuroblasts. We used an enhancer trap screen to identify the ming gene, which is transiently expressed in a subset of neuroblasts at reproducible points in their cell lineage (i.e. in neuroblast ‘sublineages’), suggesting that neuroblast identity can be altered during its cell lineage. ming encodes a predicted zinc finger protein and loss of ming function results in precise alterations in CNS gene expression, defects in axonogenesis and embryonic lethality. We propose that ming controls cell fate within neuroblast cell lineages.


2019 ◽  
Author(s):  
Wei Wang ◽  
Gang Ren ◽  
Ni Hong ◽  
Wenfei Jin

Abstract Background: CCCTC-Binding Factor (CTCF), also known as 11-zinc finger protein, participates in many cellular processes, including insulator activity, transcriptional regulation and organization of chromatin architecture. Based on single cell flow cytometry and single cell RNA-FISH analyses, our previous study showed that deletion of CTCF binding site led to a significantly increase of cellular variation of its target gene. However, the effect of CTCF on genome-wide landscape of cell-to-cell variation is unclear. Results: We knocked down CTCF in EL4 cells using shRNA, and conducted single cell RNA-seq on both wild type (WT) cells and CTCF-Knockdown (CTCF-KD) cells using Fluidigm C1 system. Principal component analysis of single cell RNA-seq data showed that WT and CTCF-KD cells concentrated in two different clusters on PC1, indicating gene expression profiles of WT and CTCF-KD cells were systematically different. Interestingly, GO terms including regulation of transcription, DNA binding, Zinc finger and transcription factor binding were significantly enriched in CTCF-KD-specific highly variable genes, indicating tissue-specific genes such as transcription factors were highly sensitive to CTCF level. The dysregulation of transcription factors potentially explain why knockdown of CTCF lead to systematic change of gene expression. In contrast, housekeeping genes such as rRNA processing, DNA repair and tRNA processing were significantly enriched in WT-specific highly variable genes, potentially due to a higher cellular variation of cell activity in WT cells compared to CTCF-KD cells. We further found cellular variation-increased genes were significantly enriched in down-regulated genes, indicating CTCF knockdown simultaneously reduced the expression levels and increased the expression noise of its regulated genes. Conclusions: To our knowledge, this is the first attempt to explore genome-wide landscape of cellular variation after CTCF knockdown. Our study not only advances our understanding of CTCF function in maintaining gene expression and reducing expression noise, but also provides a framework for examining gene function.


1998 ◽  
Vol 18 (6) ◽  
pp. 3120-3129 ◽  
Author(s):  
Youngsook Lee ◽  
Tetsuo Shioi ◽  
Hideko Kasahara ◽  
Shawn M. Jobe ◽  
Russell J. Wiese ◽  
...  

ABSTRACT Specification and differentiation of the cardiac muscle lineage appear to require a combinatorial network of many factors. The cardiac muscle-restricted homeobox protein Csx/Nkx2.5 (Csx) is expressed in the precardiac mesoderm as well as the embryonic and adult heart. Targeted disruption of Csx causes embryonic lethality due to abnormal heart morphogenesis. The zinc finger transcription factor GATA4 is also expressed in the heart and has been shown to be essential for heart tube formation. GATA4 is known to activate many cardiac tissue-restricted genes. In this study, we tested whether Csx and GATA4 physically associate and cooperatively activate transcription of a target gene. Coimmunoprecipitation experiments demonstrate that Csx and GATA4 associate intracellularly. Interestingly, in vitro protein-protein interaction studies indicate that helix III of the homeodomain of Csx is required to interact with GATA4 and that the carboxy-terminal zinc finger of GATA4 is necessary to associate with Csx. Both regions are known to directly contact the cognate DNA sequences. The promoter-enhancer region of the atrial natriuretic factor (ANF) contains several putative Csx binding sites and consensus GATA4 binding sites. Transient-transfection assays indicate that Csx can activate ANF reporter gene expression to the same extent that GATA4 does in a DNA binding site-dependent manner. Coexpression of Csx and GATA4 synergistically activates ANF reporter gene expression. Mutational analyses suggest that this synergy requires both factors to fully retain their transcriptional activities, including the cofactor binding activity. These results demonstrate the first example of homeoprotein and zinc finger protein interaction in vertebrates to cooperatively regulate target gene expression. Such synergistic interaction among tissue-restricted transcription factors may be an important mechanism to reinforce tissue-specific developmental pathways.


2021 ◽  
Author(s):  
Melih Agraz ◽  
Umut Agyuz ◽  
E. Celeste Welch ◽  
Kaymaz Yasin ◽  
Kuyumcu Birol

Abstract Background Metastasis is one of the most challenging problems in cancer diagnosis and treatment, as its causes have not been yet well characterized. Prediction of the metastatic status of breast cancer is important in cancer research because it has the potential to save lives. However, the systems biology behind metastasis is complex and driven by a variety of factors beyond those that have already been characterized for various cancer types. Furthermore, prediction of cancer metastasis is a challenging task due to the variation in parameters and conditions specific to individual patients and mutation of the sub-types. Results In this paper, we apply tree-based machine learning algorithms for gene expression data analysis in the estimation of metastatic potentials within a group of 490 breast cancer patients. Hence, we utilize tree-based machine learning algorithms, decision trees, gradient boosting, and extremely randomized trees to assess the variable importance.Conclusions We obtained highly accurate values from all three algorithms, we observed the highest accuracy from the Gradient Boost method which is 0.8901. Finally, we were able to determine the 10 most important genetic variables used in the boosted algorithms, as well as their respective importance scores and biological importance. Common important genes for our algorithms are found as CD8, PB1, THP-1. CD8, also known as CD8A is a receptor for the TCR, or T-cell receptor, which facilitates cytotoxic T-cell activity and its association with cancer is defined in the paper. PB1, PBRM1 or polybromo 1 is a tumor suppressor gene. THP-1 or GLI2 is a zinc finger protein referred to as ”Glioma-Associated Oncogene Family Zinc Finger 2”. This gene encodes a protein for the zinc finger, which binds DNA and mediate Sonic hedgehog signaling (SHH). Disruption in the SHH pathway have long been associated with cancer and cellular proliferation.


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