Maternally provided LSD1/KDM1A enables the maternal-to-zygotic transition and prevents defects that manifest postnatally

Somatic cell nuclear transfer has established that the oocyte contains maternal factors with epigenetic reprogramming capacity. Yet the identity and function of these maternal factors during the gamete to embryo transition remains poorly understood. In C. elegans, LSD1/KDM1A enables this transition by removing H3K4me2 and preventing the transgenerational inheritance of transcription patterns. Here we show that loss of maternal LSD1/KDM1A in mice results in embryonic arrest at the 1-2 cell stage, with arrested embryos failing to undergo the maternal-to-zygotic transition. This suggests that LSD1/KDM1A maternal reprogramming is conserved. Moreover, partial loss of maternal LSD1/KDM1A results in striking phenotypes weeks after fertilization; including perinatal lethality and abnormal behavior in surviving adults. These maternal effect hypomorphic phenotypes are associated with alterations in DNA methylation and expression at imprinted genes. These results establish a novel mammalian paradigm where defects in early epigenetic reprogramming can lead to defects that manifest later in development.

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Hcp-1, a Protein Involved in Chromosome Segregation, Is Localized to the Centromere of Mitotic Chromosomes in Caenorhabditis elegans

The Journal of Cell Biology ◽

10.1083/jcb.147.3.471 ◽

1999 ◽

Vol 147 (3) ◽

pp. 471-480 ◽

Cited By ~ 54

Author(s):

Landon L. Moore ◽

Mike Morrison ◽

Mark B. Roth

Keyword(s):

Caenorhabditis Elegans ◽

Chromosome Segregation ◽

Chromosome Structure ◽

Sequence Database ◽

Mitotic Chromosomes ◽

Expression Screening ◽

C Elegans ◽

Genome Sequence Database ◽

And Function ◽

Embryonic Arrest

To learn more about holocentric chromosome structure and function, we generated a monoclonal antibody (mAb), 6C4, that recognizes the poleward face of mitotic chromosomes in Caenorhabditis elegans. Early in mitosis, mAb 6C4 stains dots throughout the nucleoplasm. Later in prophase, mAb 6C4 stains structures on opposing faces of chromosomes which orient towards the centrosomes at metaphase. Colocalization with an antibody against a centromeric histone H3–like protein and the MPM-2 antibody, which identifies a kinetochore-associated phosphoepitope present in a variety of organisms, shows that the mAb 6C4 staining is present adjacent to the centromere. Expression screening using mAb 6C4 identified a protein in C. elegans that we named HCP-1 (for holocentric protein 1). We also identified a second protein from the C. elegans genome sequence database, HCP-2, that is 54% similar to HCP-1. When expression of HCP-1 is reduced by RNA interference (RNAi), staining with mAb 6C4 is eliminated, indicating that hcp-1 encodes the major mAb 6C4 antigen. RNAi with hcp-1 and hcp-2 together results in aberrant anaphases and embryonic arrest at ∼100 cells with different amounts of DNA in individual nuclei. These results suggest that HCP-1 is a centromere-associated protein that is involved in the fidelity of chromosome segregation.

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The dual role of N6-methyladenosine on mouse maternal RNAs and 2-cell specific RNAs revealed by ULI-MeRIP sequencing

10.1101/2021.12.13.472368 ◽

2021 ◽

Author(s):

You Wu ◽

Xiaocui Xu ◽

Meijie Qi ◽

Chuan Chen ◽

Meiling Zhang ◽

...

Keyword(s):

Transposable Elements ◽

Rna Stability ◽

Dual Role ◽

Cell Stage ◽

Developmental Processes ◽

Stage Specificity ◽

Maternal To Zygotic Transition ◽

Context Specific ◽

And Function

N6-methyladenosine (m6A) and its regulatory components play critical roles in various developmental processes in mammals(1-5). However, the landscape and function of m6A in the maternal-to-zygotic transition (MZT) remain unclear due to limited materials. Here, by developing an ultralow-input MeRIP-seq method, we revealed the dynamics of the m6A RNA methylome during the MZT process in mice. We found that more than 1/3 maternal decay and 2/3 zygotic mRNAs were modified by m6A. Moreover, m6As are highly enriched in the RNA of transposable elements MTA and MERVL, which are highly expressed in oocytes and 2-cell embryos, respectively. Notably, maternal depletion of Kiaa1429, a component of the m6A methyltransferase complex, leads to a reduced abundance of m6A-marked maternal RNAs, including both genes and MTA, in GV oocytes, indicating m6A-dependent regulation of RNA stability in oocytes. Interestingly, when the writers were depleted, some m6A-marked 2-cell specific RNAs, including Zscan4 and MERVL, appeared normal at the 2-cell stage but failed to be decayed at later stages, suggesting that m6A regulates the clearance of these transcripts. Together, our study uncovered that m6As function in context-specific manners during MZT, which ensures the transcriptome stability of oocytes and regulates the stage specificity of zygotic transcripts after fertilization.

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CoREST has a conserved role in facilitating SPR-5/LSD1 maternal reprogramming of histone methylation

10.1101/2021.05.17.444472 ◽

2021 ◽

Author(s):

Brandon S Carpenter ◽

Alyssa M Scott ◽

Robert J Goldin ◽

Sindy R Chavez ◽

Dexter A Myrick ◽

...

Keyword(s):

Gene Expression ◽

Point Mutation ◽

Histone Methylation ◽

Epigenetic Reprogramming ◽

Germline Development ◽

Repressor Protein ◽

C Elegans ◽

Demethylase Activity ◽

Perinatal Lethality ◽

Histone Modifying Enzymes

Maternal reprogramming of histone methylation is critical for reestablishing totipotency in the zygote, but how histone modifying enzymes are regulated during maternal reprogramming is not well characterized. To address this gap, we asked whether maternal reprogramming by the H3K4me1/2 demethylase SPR-5/LSD1/KDM1A, is regulated by the co-repressor protein, SPR-1/CoREST in C. elegans and mice. In C. elegans, SPR-5 functions as part of a reprogramming switch together with the H3K9 methyltransferase MET-2. By examining germline development, fertility and gene expression in double mutants between spr-1 and met-2, we find that spr-1 mutants are partially compromised for spr-5; met-2 reprogramming. In mice, we generated a separation of function Lsd1 M448V point mutation that compromises CoREST binding, but only slightly affects LSD1 demethylase activity. When maternal LSD1 in the oocyte is derived exclusively from this allele, the progeny phenocopy the increased perinatal lethality that we previously observed when LSD1 was reduced maternally. Together, these data are consistent with CoREST having a conserved function in facilitating maternal LSD1 epigenetic reprogramming.

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The NALCN Channel Regulator UNC-80 Functions in a Subset of Interneurons To Regulate Caenorhabditis elegans Reversal Behavior

G3 Genes|Genome|Genetics ◽

10.1534/g3.119.400692 ◽

2019 ◽

Vol 10 (1) ◽

pp. 199-210 ◽

Cited By ~ 1

Author(s):

Chuanman Zhou ◽

Jintao Luo ◽

Xiaohui He ◽

Qian Zhou ◽

Yunxia He ◽

...

Keyword(s):

Plant Hormone ◽

Neuronal Excitability ◽

Resting Membrane Potential ◽

Loss Of Function ◽

Wild Type ◽

C Elegans ◽

Link Type ◽

Complex Functions ◽

And Function ◽

Multiple Loss

NALCN (Na+leak channel, non-selective) is a conserved, voltage-insensitive cation channel that regulates resting membrane potential and neuronal excitability. UNC79 and UNC80 are key regulators of the channel function. However, the behavioral effects of the channel complex are not entirely clear and the neurons in which the channel functions remain to be identified. In a forward genetic screen for C. elegans mutants with defective avoidance response to the plant hormone methyl salicylate (MeSa), we isolated multiple loss-of-function mutations in unc-80 and unc-79. C. elegans NALCN mutants exhibited similarly defective MeSa avoidance. Interestingly, NALCN, unc-80 and unc-79 mutants all showed wild type-like responses to other attractive or repelling odorants, suggesting that NALCN does not broadly affect odor detection or related forward and reversal behaviors. To understand in which neurons the channel functions, we determined the identities of a subset of unc-80-expressing neurons. We found that unc-79 and unc-80 are expressed and function in overlapping neurons, which verified previous assumptions. Neuron-specific transgene rescue and knockdown experiments suggest that the command interneurons AVA and AVE and the anterior guidepost neuron AVG can play a sufficient role in mediating unc-80 regulation of the MeSa avoidance. Though primarily based on genetic analyses, our results further imply that MeSa might activate NALCN by direct or indirect actions. Altogether, we provide an initial look into the key neurons in which the NALCN channel complex functions and identify a novel function of the channel in regulating C. elegans reversal behavior through command interneurons.

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STAT3 Is an Upstream Regulator of Granzyme G in the Maternal-To-Zygotic Transition of Mouse Embryos

International Journal of Molecular Sciences ◽

10.3390/ijms22010460 ◽

2021 ◽

Vol 22 (1) ◽

pp. 460

Author(s):

Huan Ou-Yang ◽

Shinn-Chih Wu ◽

Li-Ying Sung ◽

Shiao-Hsuan Yang ◽

Shang-Hsun Yang ◽

...

Keyword(s):

Transcription Factor ◽

Transcription Factors ◽

Fluorescent Protein ◽

Mouse Embryos ◽

Cell Nuclei ◽

Cell Stage ◽

Promoter Assay ◽

Maternal To Zygotic Transition ◽

Mouse Zygotes ◽

Time Specific

The maternal-to-zygotic transition (MZT), which controls maternal signaling to synthesize zygotic gene products, promotes the preimplantation development of mouse zygotes to the two-cell stage. Our previous study reported that mouse granzyme g (Gzmg), a serine-type protease, is required for the MZT. In this study, we further identified the maternal factors that regulate the Gzmg promoter activity in the zygote to the two-cell stage of mouse embryos. A full-length Gzmg promoter from mouse genomic DNA, FL-pGzmg (−1696~+28 nt), was cloned, and four deletion constructs of this Gzmg promoter, Δ1-pGzmg (−1369~+28 nt), Δ2-pGzmg (−939~+28 nt), Δ3-pGzmg (−711~+28 nt) and Δ4-pGzmg (−417~+28 nt), were subsequently generated. Different-sized Gzmg promoters were used to perform promoter assays of mouse zygotes and two-cell stage embryos. The results showed that Δ4-pGzmg promoted the highest expression level of the enhanced green fluorescent protein (EGFP) reporter in the zygotes and two-cell embryos. The data suggested that time-specific transcription factors upregulated Gzmg by binding cis-elements in the −417~+28-nt Gzmg promoter region. According to the results of the promoter assay, the transcription factor binding sites were predicted and analyzed with the JASPAR database, and two transcription factors, signal transducer and activator of transcription 3 (STAT3) and GA-binding protein alpha (GABPα), were identified. Furthermore, STAT3 and GABPα are expressed and located in zygote pronuclei and two-cell nuclei were confirmed by immunofluorescence staining; however, only STAT3 was recruited to the mouse zygote pronuclei and two-cell nuclei injected with the Δ4-pGzmg reporter construct. These data indicated that STAT3 is a maternal transcription factor and may upregulate Gzmg to promote the MZT. Furthermore, treatment with a STAT3 inhibitor, S3I-201, caused mouse embryonic arrest at the zygote and two-cell stages. These results suggest that STAT3, a maternal protein, is a critical transcription factor and regulates Gzmg transcription activity in preimplantation mouse embryos. It plays an important role in the maternal-to-zygotic transition during early embryonic development.

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C. elegans germ granules require both assembly and localized regulators for mRNA repression

Nature Communications ◽

10.1038/s41467-021-21278-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Scott Takeo Aoki ◽

Tina R. Lynch ◽

Sarah L. Crittenden ◽

Craig A. Bingman ◽

Marvin Wickens ◽

...

Keyword(s):

Liquid Droplet ◽

Scaffolding Protein ◽

P Granules ◽

C Elegans ◽

Cytoplasmic Rna ◽

And Function ◽

Rnp Granules ◽

Key Residues ◽

Reporter Mrna

AbstractCytoplasmic RNA–protein (RNP) granules have diverse biophysical properties, from liquid to solid, and play enigmatic roles in RNA metabolism. Nematode P granules are paradigmatic liquid droplet granules and central to germ cell development. Here we analyze a key P granule scaffolding protein, PGL-1, to investigate the functional relationship between P granule assembly and function. Using a protein–RNA tethering assay, we find that reporter mRNA expression is repressed when recruited to PGL-1. We determine the crystal structure of the PGL-1 N-terminal region to 1.5 Å, discover its dimerization, and identify key residues at the dimer interface. Mutations of those interface residues prevent P granule assembly in vivo, de-repress PGL-1 tethered mRNA, and reduce fertility. Therefore, PGL-1 dimerization lies at the heart of both P granule assembly and function. Finally, we identify the P granule-associated Argonaute WAGO-1 as crucial for repression of PGL-1 tethered mRNA. We conclude that P granule function requires both assembly and localized regulators.

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hlh-12, a gene that is necessary and sufficient to promote migration of gonadal regulatory cells in C. elegans, evolved within the Caenorhabditis clade

Genetics ◽

10.1093/genetics/iyab127 ◽

2021 ◽

Author(s):

Hana E Littleford ◽

Karin Kiontke ◽

David H A Fitch ◽

Iva Greenwald

Keyword(s):

Ectopic Expression ◽

Morphological Diversity ◽

Nematode Species ◽

Bhlh Protein ◽

Vulval Development ◽

C Elegans ◽

Form And Function ◽

Somatic Gonad ◽

And Function ◽

Necessary And Sufficient

Abstract Specialized cells of the somatic gonad primordium of nematodes play important roles in the final form and function of the mature gonad. C. elegans hermaphrodites are somatic females that have a two-armed, U-shaped gonad that connects to the vulva at the midbody. The outgrowth of each gonad arm from the somatic gonad primordium is led by two female Distal Tip Cells (fDTC), while the Anchor Cell (AC) remains stationary and central to coordinate uterine and vulval development. The bHLH protein HLH-2 and its dimerization partners LIN-32 and HLH-12 had previously been shown to be required for fDTC specification. Here, we show that ectopic expression of both HLH-12 and LIN-32 in cells with AC potential transiently transforms them into fDTC-like cells. Furthermore, hlh-12 was known to be required for the fDTCs to sustain gonad arm outgrowth. Here, we show that ectopic expression of HLH-12 in the normally stationary AC causes displacement from its normal position, and that displacement likely results from activation of the leader program of fDTCs because it requires genes necessary for gonad arm outgrowth. Thus, HLH-12 is both necessary and sufficient to promote gonadal regulatory cell migration. As differences in female gonadal morphology of different nematode species reflect differences in the fate or migratory properties of the fDTCs or of the AC, we hypothesized that evolutionary changes in the expression of hlh-12 may underlie evolution of such morphological diversity. However, we were unable to identify an hlh-12 ortholog outside of Caenorhabditis. Instead, by performing a comprehensive phylogenetic analysis of all Class II bHLH proteins in multiple nematode species, we found that HLH-12 evolved within the Caenorhabditis clade, possibly by duplicative transposition of hlh-10. Our analysis suggests that control of gene regulatory hierarchies for gonadogenesis can be remarkably plastic during evolution without adverse phenotypic consequence.

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Cardiac expression of a gain-of-function α5-integrin results in perinatal lethality

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2001.280.1.h361 ◽

2001 ◽

Vol 280 (1) ◽

pp. H361-H367 ◽

Cited By ~ 17

Author(s):

Maria L. Valencik ◽

John A. McDonald

Keyword(s):

Cardiac Development ◽

Wild Type ◽

Integrin Receptors ◽

Gain Of Function ◽

Transgenic Expression ◽

Physiological Regulation ◽

Myocyte Differentiation ◽

Perinatal Lethality ◽

And Function

Communication between the extracellular matrix and the intracellular signal transduction and cytoskeletal system is mediated by integrin receptors. α5β1-Integrin and its cognate ligand fibronectin are essential in development of mesodermal structures, myocyte differentiation, and normal cardiac development. To begin to explore the potential roles of α5β1-integrin specifically in cardiomyocytes, we used a transgenic expression strategy. We overexpressed two forms of the human α5-integrin in cardiomyocytes: the full-length wild-type α5-integrin and a putative gain-of-function mutation created by truncating the cytoplasmic domain, designated α5-1-integrin. Overexpression of the wild-type α5-integrin has no detectable adverse effects in the mouse, whereas expression of α5-1-integrin caused electrocardiographic abnormalities, fibrotic changes in the ventricle, and perinatal lethality. Thus physiological regulation of integrin function appears essential for maintenance of normal cardiomyocyte structure and function. This strengthens the role of inside-out signaling in regulation of integrins in vivo and suggests that integrins and associated signaling molecules are important in cardiomyocyte function.

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The Genomic Distribution and Function of Histone Variant HTZ-1 during C. elegans Embryogenesis

PLoS Genetics ◽

10.1371/journal.pgen.1000187 ◽

2008 ◽

Vol 4 (9) ◽

pp. e1000187 ◽

Cited By ~ 67

Author(s):

Christina M. Whittle ◽

Karissa N. McClinic ◽

Sevinc Ercan ◽

Xinmin Zhang ◽

Roland D. Green ◽

...

Keyword(s):

Histone Variant ◽

Genomic Distribution ◽

C Elegans ◽

And Function

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Three C. elegans Rac proteins and several alternative Rac regulators control axon guidance, cell migration and apoptotic cell phagocytosis

Development ◽

10.1242/dev.128.22.4475 ◽

2001 ◽

Vol 128 (22) ◽

pp. 4475-4488 ◽

Cited By ~ 7

Author(s):

Erik A. Lundquist ◽

Peter W. Reddien ◽

Erika Hartwieg ◽

H. Robert Horvitz ◽

Cornelia I. Bargmann

Keyword(s):

Cell Migration ◽

Axon Guidance ◽

Apoptotic Cell ◽

Regulatory Proteins ◽

Axon Pathfinding ◽

C Elegans ◽

Cell Corpse ◽

And Function ◽

Redundant Functions ◽

Caenorhabditis Elegans Genome

The Caenorhabditis elegans genome contains three rac-like genes, ced-10, mig-2, and rac-2. We report that ced-10, mig-2 and rac-2 act redundantly in axon pathfinding: inactivating one gene had little effect, but inactivating two or more genes perturbed both axon outgrowth and guidance. mig-2 and ced-10 also have redundant functions in some cell migrations. By contrast, ced-10 is uniquely required for cell-corpse phagocytosis, and mig-2 and rac-2 have only subtle roles in this process. Rac activators are also used differentially. The UNC-73 Trio Rac GTP exchange factor affected all Rac pathways in axon pathfinding and cell migration but did not affect cell-corpse phagocytosis. CED-5 DOCK180, which acts with CED-10 Rac in cell-corpse phagocytosis, acted with MIG-2 but not CED-10 in axon pathfinding. Thus, distinct regulatory proteins modulate Rac activation and function in different developmental processes.

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