Pb103 Regulates Zygote/Ookinete Development in Plasmodium berghei via Double Zinc Finger Domains

Sexual reproduction of Plasmodium parasites takes place in anopheline mosquitoes, where male and female gametes fuse to form zygotes and then ookinetes. These processes are orchestrated by stage-specific protein expression, which is mediated in part by translational repression. Accumulating evidence shows that RNA binding proteins (RBPs) play crucial roles in these processes. Here, we report the characterization of P. berghei 103 (Pb103), which encodes a protein possessing double zinc finger domains (ZFs), an RBP. Reporter parasites expressing azami green fluorescent protein (AGFP) under the endogenous Pb103 gene promoter (Pb103-AGFP reporter) showed that the AGFP fluorescent signal was detected from gametes to ookinetes, while AGFP mRNA was translationally repressed in female gametocytes. The Pb103-disrupted parasites (Pb103(−)) grew and produced gametocytes with similar efficiencies to those of wild-type parasites. However, no oocysts were formed in mosquitoes fed Pb103(−). An in vitro fertilization assay showed abortion at the zygote stage in Pb103(−), suggesting that Pb103 plays a critical role in zygote/ookinete development. Cross-fertilization assays with Pb103(−) and male- or female-sterile parasites revealed that Pb103 was essential exclusively for female gametes. To identify the domains critical for zygote/ookinete development, transgenic parasites expressing partially deleted Pb103 were generated and assayed for ookinete maturation. As a result, deleting either of two ZFs but not the C-terminal region abolished zygote/ookinete development, highlighting the indispensable roles of ZFs in parasite sexual development, most likely via translational repression.

Zinc Finger Proteins in Neuro-Related Diseases Progression

Zinc finger proteins (ZNF) are among the most abundant proteins in eukaryotic genomes. It contains several zinc finger domains that can selectively bind to certain DNA or RNA and associate with proteins, therefore, ZNF can regulate gene expression at the transcriptional and translational levels. In terms of neurological diseases, numerous studies have shown that many ZNF are associated with neurological diseases. The purpose of this review is to summarize the types and roles of ZNF in neuropsychiatric disorders. We will describe the structure and classification of ZNF, then focus on the pathophysiological role of ZNF in neuro-related diseases and summarize the mechanism of action of ZNF in neuro-related diseases.

Insilico Search for Potential DNA Binding Domain of Human Zinc Finger Protein Sp1

Specificity protein 1 (Sp1) belongs to a family of ubiquitously expressed, C2H2-type zinc finger-containing DNA binding proteins that activate or repress transcription of many genes in response to physiological and pathological stimuli. Specificity protein 1 is considered to be a constitutively expressed transcription factor and has been implicated in the regulation of a wide variety of housekeeping genes, tissue-specific genes, and genes involved in the regulation of growth. In order to determine the binding affinity of Sp1 zinc finger domains, the total energy for each and every possible combination of GC box and Zn finger motifs using Hex server, Model IT software’s is calculated. According to the findings of this study, the design of multi-zinc finger proteins with a variety of sequence specificities will be easier to accomplish. Among the three motifs present in Specificity protein 1, motifs 1 and 2 have higher binding affinity than motif 3.

ZNF224 Protein: Multifaceted Functions Based on Its Molecular Partners

The transcription factor ZNF224 is a Kruppel-like zinc finger protein that consists of 707 amino acids and contains 19 tandemly repeated C2H2 zinc finger domains that mediate DNA binding and protein–protein interactions. ZNF224 was originally identified as a transcriptional repressor of genes involved in energy metabolism, and it was demonstrated that ZNF224-mediated transcriptional repression needs the interaction of its KRAB repressor domain with the co-repressor KAP1 and its zinc finger domains 1–3 with the arginine methyltransferase PRMT5. Furthermore, the protein ZNF255 was identified as an alternative isoform of ZNF224 that possesses different domain compositions mediating distinctive functional interactions. Subsequent studies showed that ZNF224 is a multifunctional protein able to exert different transcriptional activities depending on the cell context and the variety of its molecular partners. Indeed, it has been shown that ZNF224 can act as a repressor, an activator and a cofactor for other DNA-binding transcription factors in different human cancers. Here, we provide a brief overview of the current knowledge on the multifaceted interactions of ZNF224 and the resulting different roles of this protein in various cellular contexts.

Expression of Evi-1 Gene in Leukaemia: Diagnostic and Prognostic Perspective

Leukaemias are malignant neoplasms characterized by disorderly, purposeless proliferation of white blood cells with abundance of one cell type. The exact aetiology of leukaemias is still yet to be fully understood. However, it is generally believed that neoplasm is caused by genetic mutation, chromosomal translocation, or activation of certain oncogenes. There are also nuclear oncogenes which are also vital genes in normal cell proliferation and differentiation, often being pivotal genes in developmental and cell cycle regulation. They are also important in cancer progression. Ecotropic viral integration site (EVI-1), a nuclear oncogene has been implicated in the progression of some leukaemias. EVI-1 gene is located on the human chromosome 3 band q24-q28 and spans over 100 kb. The EVI-1 gene encodes a 145 kDa protein of the zinc-finger family which is an essential transcription factor for appropriate murine and human development and is also associated with some leukaemias, following ectopic expression. EVI-1 protein is divided into two main regions: The N-terminal region that contains zinc finger domains (ZFi) and C-terminal region containing three zinc finger domains (ZFii) and a sequence of acidic amino acid. This review summarizes the biological, leukaemogenetic/oncogenic roles and biochemical properties of EVI-1. It further discusses the diagnostic and prognostic implication of EVI-1 in some leukaemias, encouraging incorporation of routine assay of EVI-1 in diagnosis and prognostic monitoring of leukaemias.

TRIM28 regulates Kaiso SUMOylation

Tripartite motif protein 28 (TRIM28), a universal mediator of Krüppel-associated box domain zinc fingers (KRAB-ZNFs), is known to regulate DNA methylation of many repetitive elements and several imprinted loci. TRIM28 serves as a scaffold unit that is essential for the formation of stable repressor complexes. In the present study we found that TRIM28 is a binding partner for methyl-DNA binding protein Kaiso. Kaiso is a transcription factor that belongs to the BTB/POZ -zinc finger family. Recent data suggest that deficiency of Kaiso led to reduction of DNA methylation within the imprinting control region of H19/IGF2. Thus, we hypothesized that Kaiso and TRIM28 may cooperate to control methylated genes. We demonstrated that Kaiso interacts with TRIM28 via its two domains: BTB/POZ and three zinc finger domains. When bound to Kaiso’s zinc finger domains TRIM28 weakens their interactions with methylated DNA in vitro. Specific association of TRIM28 with BTB/POZ domain causes Kaiso hyperSUMOylation. Altogether our data describe a putative role of TRIM28 as a regulator of Kaiso activity.