bioRxiv Science⌕ Search

Biology subjects

Manske, G.

Publications and source records attributed to Manske, G..

4 recordsLinked to original sources

Maternal CENP-C restores centromere symmetry in mammalian zygotes to ensure proper chromosome segregation

Across metazoan species, the centromere-specific histone variant CENP-A is essential for accurate chromosome segregation, yet its regulation at the parental-to-zygote transition in mammals is poorly understood. To address this, we developed a CENP-A-mScarlet knock-in mouse model, which revealed sex-specific dynamics: mature sperm retains 10% of the CENP-A levels present in MII-oocytes. However, in zygotes prior to the first mitosis, this difference is resolved, using maternally inherited cytoplasmic-CENP-A. Notably, the increase in CENP-A at paternal centromeres is independent of sensing CENP-A asymmetry or the presence of maternal chromosomes. Instead, CENP-A equalization relies on asymmetric recruitment of maternal CENP-C to paternal centromeres. Depletion of maternal CENP-A decreases total CENP-A in pronuclei without disrupting equalization. In contrast, reducing maternal CENP-C or disruption of its dimerization domains impairs CENP-A equalization and chromosome segregation. Therefore, maternal CENP-C acts a key epigenetic regulator that resets centromeric symmetry at fertilization to preserve genome integrity. Highlights[bullet] CENP-A asymmetry between sperm and oocyte centromeres is a conserved feature from flies to mammals including mice and humans. [bullet]CENP-A asymmetry between parental centromeres is resolved prior to the first zygotic division via maternally inherited, cytoplasmic CENP-A. [bullet]Zygotic CENP-A levels in zygotes are regulated in a pronucleus-autonomous manner. [bullet]CENP-A equalization relies on asymmetric CENP-C recruitment to the paternal pronucleus and requires CENP-C dimerization. Key TermsCentromere; CENP-A; CENP-C; sperm; oocyte; zygote; intergenerational; epigenetics; mouse

genetics↗

Asymmetric Histone Inheritance Regulates Differential Transcription Re-initiation and Cell Fate Decisions in Mouse Olfactory Horizontal Basal Cells

The olfactory epithelium (OE) possesses an adult stem cell population, the horizontal basal cells (HBCs), to permit lifelong tissue regeneration. Here we show that HBCs exhibit asymmetric inheritance of histone H4 but not H2A-H2B during OE regeneration in mice. Primary HBC cultures further revealed asymmetric histone inheritance for H3 and H3.3. Upon mitotic exit, asymmetric histone inheritance correlates with asynchronous transcription re-initiation and differential enrichment of p63, a key transcription factor for HBC cell fate. Disruption of asymmetric histone inheritance abolished these asymmetric cellular features and attenuated OE regeneration and smell behavior recovery. Single-cell RNA sequencing of paired HBC daughters in culture further supported asymmetric multilineage cell fate priming. Together, these findings reveal asymmetric histone inheritance in a mammalian adult stem cell lineage and highlight its biological significance in neural tissue regeneration and animal behavior.

developmental biology↗

Equalizing epigenetically imprinted centromeres in early mammalian embryos

The CENP-A histone variant epigenetically defines centromeres, where its levels and locations are precisely maintained through mitotic cell divisions. However, differences in centromere CENP-A propagation in soma versus female/male germline remains poorly understood. Here, we generated CenpamScarlet mice and followed CENP-A dynamics in gametes, zygotes, and embryos. We found that, unlike somatic cells, progenitor female and male germ cells carry high centromeric CENP-A levels that decrease upon terminal differentiation. The reduction in CENP-A is differentially regulated between sexes, resulting in a ten-fold higher level in oocytes compared to sperm. In the zygote, the parent-of-origin CENP-A asymmetry is equalized prior to initial S-phase by redistribution of nuclear CENP-A from maternal to paternal chromosomes. Redistribution of CENP-A requires both CDK1/2 and PLK1 centromeric machinery. These experiments provide direct evidence for resetting of epigenetically imprinted centromeres in early pronuclear stage embryos and imply a mechanism to sense the non-equivalency of parental chromosomes. HighlightsO_LIIncreased CENP-A density at centromeres is a conserved property of germline stem cells while CENP-A reduction is coincident with germ cell differentiation C_LIO_LIPaternal and maternal CENP-A containing nucleosomes are intergenerationally inherited C_LIO_LICENP-A density at centromeres differs between male and female mature gametes C_LIO_LIUpon fertilization, maternal nuclear CENP-A is redistributed to equalize with parental CENP-A C_LIO_LICENP-C and MIS18BP1 are asymmetrically enriched in the parental pronuclei in accordance with CENP-A asymmetry. C_LIO_LILicensing for centromere equalization begins before zygotic DNA replication C_LI

developmental biology↗

Single-cell RNA sequencing of human, macaque, and mouse testes uncovers conserved and divergent features of mammalian spermatogenesis

Spermatogenesis is a highly regulated process that produces sperm to transmit genetic information to the next generation. Although extensively studied in mice, our current understanding of primate spermatogenesis is limited to populations defined by state-specific markers defined from rodent data. As between-species differences have been reported in the process duration and cellular differentiation hierarchy, it remains unclear how molecular markers and cell states are conserved or have diverged from mice to man. To address this challenge, we employ single-cell RNA-sequencing to identify transcriptional signatures of major germ and somatic cell-types of the testes in human, macaque and mice. This approach reveals differences in expression throughout spermatogenesis, including the stem/progenitor pool of spermatogonia, classical markers of differentiation, potential regulators of meiosis, the kinetics of RNA turnover during spermatid differentiation, and germ cell-soma communication. These datasets provide a rich foundation for future targeted mechanistic studies of primate germ cell development and in vitro gametogenesis.

genetics↗