Biology subjects

Malik, V.

Publications and source records attributed to Malik, V..

4 recordsLinked to original sources

bioRxiv2023

ZFP281 coordinates DNMT3 and TET1 for transcriptional and epigenetic control in pluripotent state transitions

The progression from naive through formative to primed in vitro pluripotent stem cell states recapitulates the development of the epiblast in vivo during the peri-implantation period of mammalian development. Activation of the de novo DNA methyltransferases and reorganization of transcriptional and epigenetic landscapes are key events occurring during these pluripotent state transitions. However, the upstream regulators that coordinate these events are relatively underexplored. Here, using Zfp281 knockout mouse and degron knock-in cell models, we uncover the direct transcriptional activation of Dnmt3a/3b by ZFP281 in pluripotent stem cells. Chromatin co-occupancy of ZFP281 and DNA hydroxylase TET1, dependent on the formation of R loops in ZFP281-targeted gene promoters, undergoes a "high-low-high" bimodal pattern regulating dynamic DNA methylation and gene expression during the naive-formative-primed transitions. ZFP281 also safeguards DNA methylation in maintaining primed pluripotency. Our study demonstrates a previously unappreciated role for ZFP281 in coordinating DNMT3A/3B and TET1 functions to promote pluripotent state transitions. In BriefThe naive, formative, and primed pluripotent states and their interconversions recapitulate pluripotency continuum during early development. Huang and colleagues investigated the transcriptional programs during successive pluripotent state transitions and revealed an essential role for ZFP281 in coordinating DNMT3A/3B and TET1 to establish the DNA methylation and gene expression programs during the transitions. HighlightsO_LIZFP281 activates Dnmt3a/3b in vitro in pluripotent stem cells and in vivo in epiblast. C_LIO_LIZFP281 and TET1 undergo bimodal chromatin occupancy in pluripotent state transitions. C_LIO_LIChromatin-binding of ZFP281 and TET1 depends on the formation of R-loops at promoters. C_LIO_LIZFP281 is necessary for the establishment and maintenance of primed pluripotency. C_LI

developmental biology↗

bioRxiv2023

The pluripotency factor Tex10 finetunes Wnt signaling for PGC and male germline development

Testis-specific transcript 10 (Tex10) is a critical factor for pluripotent stem cell maintenance and preimplantation development. Here, we dissect its late developmental roles in primordial germ cell (PGC) specification and spermatogenesis using cellular and animal models. We discover that Tex10 binds the Wnt negative regulator genes, marked by H3K4me3, at the PGC-like cell (PGCLC) stage in restraining Wnt signaling. Depletion and overexpression of Tex10 hyperactivate and attenuate the Wnt signaling, resulting in compromised and enhanced PGCLC specification efficiency, respectively. Using the Tex10 conditional knockout mouse models combined with single-cell RNA sequencing, we further uncover critical roles of Tex10 in spermatogenesis with Tex10 loss causing reduced sperm number and motility associated with compromised round spermatid formation. Notably, defective spermatogenesis in Tex10 knockout mice correlates with aberrant Wnt signaling upregulation. Therefore, our study establishes Tex10 as a previously unappreciated player in PGC specification and male germline development by fine-tuning Wnt signaling.

developmental biology↗

bioRxiv2022

Enhancing Sox/Oct cooperativity induces higher-grade developmental reset

The discovery of induced pluripotent stem cell (iPSC) technology by Shinya Yamanaka has truly enabled the stem cell field. After 16 years of intense research, the delivery methods and culture media have improved but the original factors--Oct4, Sox2, Klf4, and Myc (OSKM)--remain central for driving reprogramming. Here we define structural elements in chimeric Sox2/Sox17 transcription factors that rescued the ability of nonfunctional Oct factors to induce pluripotency. Most importantly, we discovered a single amino acid swap in the DNA-binding domain of Sox2, A61V, that stabilizes the Sox/Oct heterodimer on DNA through hydrophobic interaction with Oct. The highly cooperative Sox2AV mutant enables iPSC generation with Oct4 orthologs, such as Oct2 and Oct6, as well as rescues otherwise detrimental Oct4 mutants and domain deletions. Sox2AV has a dramatic effect on the cell fate reset, significantly improving the developmental potential of OSKM iPSCs. Moreover, by swapping multiple beneficial elements of Sox17 into Sox2 we have built a chimeric super-SOX factor--Sox2-17--that delivers unprecedented reprogramming efficiency and kinetics in five tested species. Sox2-17 enhances five-, four-, and three-factor reprogramming up to hundreds of times, enables two-factor generation of human iPSCs, and allows integration-free reprogramming of otherwise non-permissive aged human, non-human primate, and cattle fibroblasts. Our study demonstrates that a complete developmental reset requires both robust activation of regulatory elements controlled by the canonical SoxOct motif and limiting cellular proliferation driven by Oct4 and Myc. A high level of Sox2 expression and Sox2/Oct4 heterodimerization emerge as the key determinants of high-grade pluripotency that fades along the naive-to-primed continuum. Transient expression of SK cocktail can restore the naivety, providing a powerful technology to induce more complete developmental reset in pluripotent cells across species.

developmental biology↗

bioRxiv2021

A TET1-PSPC1-Neat1 molecular axis modulates PRC2 functions in controlling stem cell bivalency

TET1 maintains hypomethylation at bivalent promoters through its catalytic activity in embryonic stem cells (ESCs). However, whether and how TET1 exerts catalytic activity-independent functions in regulating bivalent genes is not well understood. Using a proteomics approach, we mapped the TET1 interactome in mouse ESCs and identified PSPC1 as a novel TET1 partner. Genome-wide location analysis reveals that PSPC1 functionally associates with TET1 and Polycomb repressive complex-2 (PRC2) complex. We establish that PSPC1 and TET1 repress, and Neat1, the PSPC1 cognate lncRNA, activates the bivalent gene expression. In ESCs, Neat1 tethers the TET1-PSPC1 pair with PRC2 at bivalent promoters. During the ESC-to-formative epiblast-like stem cell (EpiLC) transition, PSPC1 and TET1 promote PRC2 chromatin occupancy at bivalent gene promoters while restricting Neat1 functions in facilitating PRC2 binding to bivalent gene transcripts. Our study uncovers a novel TET1-PSPC1-Neat1 molecular axis that modulates PRC2 binding affinity to chromatin and bivalent gene transcripts in controlling stem cell bivalency. In BriefTET1 is a transcriptional repressor for bivalent genes in pluripotent stem cells, but its mechanistic action on stem cell bivalency is unclear. Huang et al. use proteomics and genetic approaches to reveal that catalytic activity-independent functions of TET1, coordinated with the paraspeckle components PSPC1 and its cognate lncRNA Neat1, dynamically regulates stem cell bivalency by modulating PRC2 binding affinity to chromatin and bivalent gene transcripts in pluripotent state transition. HighlightsO_LIThe TET1 interactome identifies PSPC1 as a novel partner in ESCs C_LIO_LITET1 and PSPC1 repress bivalent genes by promoting PRC2 chromatin occupancy C_LIO_LINeat1 facilitates bivalent gene activation by promoting PRC2 binding to their mRNAs C_LIO_LINeat1 bridges the TET1-PSPC1 and PRC2 complexes in regulating bivalent gene transcription C_LI

developmental biology↗