The heterochromatin protein 1 (HP1) family is involved in various functions with maintenance of chromatin structure. During murine somatic cell reprogramming, we find that early depletion of HP1γ reduces the generation of induced pluripotent stem cells, while late depletion enhances the process, with a concomitant change from a centromeric to nucleoplasmic localization and elongation-associated histone H3.3 enrichment. Depletion of heterochromatin anchoring protein SENP7 increased reprogramming efficiency to a similar extent as HP1γ, indicating the importance of HP1γ release from chromatin for pluripotency acquisition. HP1γ interacted with OCT4 and DPPA4 in HP1α and HP1β knockouts and in H3K9 methylation depleted H3K9M embryonic stem cell (ESC) lines. HP1α and HP1γ complexes in ESCs differed in association with histones, the histone chaperone CAF1 complex, and specific components of chromatin-modifying complexes such as DPY30, implying distinct functional contributions. Taken together, our results reveal the complex contribution of the HP1 proteins to pluripotency.
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http://dx.doi.org/10.1016/j.stemcr.2017.12.016 | DOI Listing |
Front Biosci (Landmark Ed)
January 2025
The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University Health Science Center, 410013 Changsha, Hunan, China.
Background: α thalassemia/mental retardation syndrome X-linked (ATRX) serves as a part of the sucrose nonfermenting 2 (SNF2) chromatin-remodeling complex. In interphase, ATRX localizes to pericentromeric heterochromatin, contributing to DNA double-strand break repair, DNA replication, and telomere maintenance. During mitosis, most ATRX proteins are removed from chromosomal arms, leaving a pool near the centromere region in mammalian cells, which is critical for accurate chromosome congression and sister chromatid cohesion protection.
View Article and Find Full Text PDFBrain Struct Funct
January 2025
Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia.
In this study, we analyzed the spatio-temporal pattern of expression of specific transcription factors (PITX2, FOXA1, BARHL1, FOXP1, FOXP2) in the human fetal subthalamic nucleus and its neighboring structures from 11 postconceptional weeks (PCW) to 3 postnatal months. We found that all analyzed transcription factors are expressed already during the early fetal period (at 11 PCW). Both FOXP1- and FOXP2-immunoreactive cells were found in the subthalamic nucleus as well as in the striatum, thalamus, reticular nucleus, but not in the zona incerta.
View Article and Find Full Text PDFNat Commun
January 2025
Infinity, Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, Inserm U1291, CNRS U5051, Toulouse, France.
Protective immune responses require close interactions between conventional (Tconv) and regulatory T cells (Treg). The extracellular mediators and signaling events that regulate the crosstalk between these CD4 T cell subsets have been extensively characterized. However, how Tconv translate Treg-dependent suppressive signals at the chromatin level remains largely unknown.
View Article and Find Full Text PDFCurr Microbiol
January 2025
State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Provincial Key Laboratory for Microbial Molecular Biology, College of Life Science, Hunan Normal University, Changsha, China.
Remodelling regulatory pathways to directionally increase the efficiency of specific promoters in chassis cells is an effective strategy for the rational construction of expression systems. However, the repeated utilization of one regulator to modify the host cell to improve expression motif efficiency has a limited effect. Therefore, it is preferable to identify new regulatory factors to activate specific pathways and thus further improve the efficiency of target elements.
View Article and Find Full Text PDFThe recruitment of Heterochromatin Protein 1 (HP1) partners is essential for heterochromatin assembly and function, yet our knowledge regarding their organization in heterochromatin remains limited. Here we show that interactors engage the Drosophila HP1 (HP1a) dimer through a degenerate and expanded form of the previously identified PxVxL motif, which we now term HP1a Access Codes (HACs). These HACs reside in disordered regions, possess high conservation among Drosophila homologs, and contain alternating hydrophobic residues nested in a cluster of positively charged amino acids.
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