The Programme of Cell Type Determination in Fission Yeast

Development ◽  
1992 ◽  
pp. 75-87
Author(s):  
Benito Arcangioli ◽  
Amar J. S. Klar
Keyword(s):  
Fission Yeast ◽  
Cell Type

Cell type switching by DNA transposition in fission yeast

Nature ◽  
1983 ◽  
Vol 305 (5936) ◽  
pp. 682-688 ◽  
Author(s):  
David H. Beach
Keyword(s):  
Fission Yeast ◽  
Cell Type ◽  
Dna Transposition

scholarly journals A Recombinationally Repressed Region Between mat2 and mat3 Loci Shares Homology to Centromeric Repeats and Regulates Directionality of Mating-Type Switching in Fission Yeast

Genetics ◽  
1997 ◽  
Vol 146 (4) ◽  
pp. 1221-1238 ◽  
Author(s):  
Shiv I S Grewal ◽  
Amar J S Klar
Keyword(s):  
Fission Yeast ◽  
Mating Type ◽  
Sequencing Analysis ◽  
Cell Type ◽  
Cloning And Sequencing ◽  
Type Region ◽  
Repeat Sequences ◽  
Mating Type Switching ◽  
Cell Type Specific

Cells of the fission yeast Schizosaccharomyces pombe switch mating type by replacing genetic information at the transcriptionally active mat1 locus with sequences copied from one of two closely linked silent loci, mat2-P or mat3-M. By a process referred to as directionality of switching, cells predominantly switch to the opposite mat1 allele; the mat1-P allele preferentially recombines with mat3, while mat1-M selects the mat2. In contrast to efficient recombination at mat1, recombination within the adjoining mat2-mat3 interval is undetectable. We defined the role of sequences between mat2 and mat3, designated the K-region, in directionality as well as recombinational suppression. Cloning and sequencing analysis revealed that a part of the K-region is homologous to repeat sequences present at centromeres, which also display transcriptional and recombinational suppression. Replacement of 7.5 kb of the K-region with the ura4  + gene affected directionality in a variegated manner. Analysis of the swi6-mod locus, which was previously shown to affect directionality, in KΔ::ura4  + strains suggested the existence of at least two overlapping directionality mechanisms. Our work furthers the model that directionality is regulated by cell-type-specific organization of the heterochromatin-like structure in the mating-type region and provides evidence that the K-region contributes to silencing of the mat2-mat3 interval.

scholarly journals Euchromatin factors HULC and Set1C affect heterochromatin organization for mating-type switching in fission yeast Schizosaccharomyces pombe

2021 ◽  
Author(s):  
Alfredo Esquivel Chavez ◽  
Takahisa Maki ◽  
Hideo Tsubouchi ◽  
Testuya Handa ◽  
Hiroshi Kimura ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Mating Type ◽  
M Cells ◽  
Cell Type ◽  
M Cell ◽  
Ubiquitin Ligase Complex ◽  
Mating Type Switching ◽  
Histone H3k4 ◽  
Strand Invasion

Mating-type switching (MTS) in fission yeast Schizosaccharomyces pombe is a highly regulated gene conversion event. In the process, heterochromatic donors of genetic information are selected based on the P or M cell type and on the use of two recombination enhancers, SRE2 promoting use of mat2-P and SRE3 promoting use of mat3-M. Recently, we found that the histone H3K4 methyltransferase complex Set1C participates in donor selection, raising the question of how a complex best known for its effects in euchromatin controls recombination in heterochromatin. Here, we report that the histone H2BK119 ubiquitin ligase complex HULC functions with Set1C in MTS, as mutants in the shf1, brl1, brl2 and rad6 genes showed defects similar to Set1C mutants and belonged to the same epistasis group as set1Δ. Moreover, using H3K4R and H2BK119R histone mutants and a Set1-Y897A catalytic mutant indicated that ubiquitylation of histone H2BK119 by HULC and methylation of histone H3K4 by Set1C are functionally coupled in MTS. Cell-type biases in mutants further showed that the regulation might be by inhibiting use of the SRE3 enhancer in M cells, in favor of SRE2. Consistently, imbalanced switching in the mutants was traced to compromised association of the directionality factor Swi6 with the recombination enhancers in M cells. Based on their known effects at other chromosomal locations, we speculate that HULC and Set1C might control nucleosome mobility and strand invasion near the SRE elements. In addition, we uncovered distinct effects of HULC and Set1C on histone H3K9 methylation and gene silencing, consistent with additional functions in the heterochromatic domain.

scholarly journals Cdc23/Mcm10 Primase Generates the Lagging Strand-Specific Ribonucleotide Imprint in Fission Yeast

2018 ◽  
Author(s):  
Balveer Singh ◽  
Kamlesh K Bisht ◽  
Udita Upadhyay ◽  
Avinash Chandra Kushwaha ◽  
Jagpreet Singh Nanda ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Dna Polymerase ◽  
Parental Cell ◽  
Cell Type ◽  
Direct Role ◽  
Type Locus ◽  
Daughter Cells ◽  
Dna Strand ◽  
Lagging Strand

AbstractThe developmental asymmetry of fission yeast daughter cells derives from inheriting “older Watson” versus “older Crick” DNA strand from the parental cell, strands that are complementary but not identical with each other. A novel DNA strand-specific “imprint”, installed during DNA replication at the mating-type locus (mat1), imparts competence for cell type inter-conversion to one of the two chromosome replicas. The biochemical nature of the imprint and the mechanism of its installation are still not understood. The catalytic subunit of DNA Polymerase α (Polα) has been implicated in the imprinting process. Based on its known biochemical function, Polα might install the mat1 imprint during lagging strand synthesis. The nature of the imprint is not clear: it is either a nick or a ribonucleotide insertion. Our investigations do not support a role of Polα in nicking through putative endonuclease domains but confirm its role in installing an alkali-labile moiety as the imprint. A detailed genetic and molecular analysis reveals a direct role of the Cdc23/Mcm10 primase activity in installing the imprint in cooperation with Polα and Swi1.

Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

1982 ◽  
Vol 40 ◽  
pp. 210-211
Author(s):  
M.J. Murphy ◽  
R.R. Price ◽  
J.C. Sloman
Keyword(s):  
Cultured Cells ◽  
Human Tumor ◽  
Cell Type ◽  
Tumor Mass ◽  
Initial Cell ◽  
Cloning Assay ◽  
Human Tumor Cloning ◽  
The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

Some Observations on Changes in Denervated Taste Buds of Circumvallate Papillae of Rabbits

1969 ◽  
Vol 27 ◽  
pp. 308-309
Author(s):  
Sunao Fujimoto ◽  
Raymond G. Murray ◽  
Assia Murray
Keyword(s):  
Taste Buds ◽  
Taste Bud ◽  
Cell Type ◽  
Dark Cells ◽  
Type Iii ◽  
Circumvallate Papillae ◽  
Taste Bud Cells ◽  
Light Cells

Taste bud cells in circumvallate papillae of rabbit have been classified into three groups: dark cells; light cells; and type III cells. Unilateral section of the 9th nerve distal to the petrosal ganglion was performed in 18 animals, and changes of each cell type in the denervated buds were observed from 6 hours to 10 days after the operation.Degeneration of nerves is evident at 12 hours (Fig. 1) and by 2 days, nerves are completely lacking in the buds. Invasion by leucocytes into the buds is remarkable from 6 to 12 hours but then decreases. Their extrusion through the pore is seen. Shrinkage and disturbance in arrangement of cells in the buds can be seen at 2 days. Degenerated buds consisting of a few irregular cells and remnants of degenerated cells are present at 4 days, but buds apparently normal except for the loss of nerve elements are still present at 6 days.

Dendritic cells of the human epidermis: immuno-electron microscopic studies of la antigen reactivity

1978 ◽  
Vol 36 (2) ◽  
pp. 644-645
Author(s):  
G. Rowden ◽  
M. G. Lewis ◽  
T. M. Phillips
Keyword(s):  
Dendritic Cells ◽  
Langerhans Cells ◽  
Cell Types ◽  
Cell Type ◽  
Electron Microscopic ◽  
La Antigen ◽  
Microscopic Studies ◽  
A Cell ◽  
C3 Receptors ◽  
Antigen Reactivity

Langerhans cells of mammalian stratified squamous epithelial have proven to be an enigma since their discovery in 1868. These dendritic suprabasal cells have been considered as related to melanocytes either as effete cells, or as post divisional products. Although grafting experiments seemed to demonstrate the independence of the cell types, much confusion still exists. The presence in the epidermis of a cell type with morphological features seemingly shared by melanocytes and Langerhans cells has been especially troublesome. This so called "indeterminate", or " -dendritic cell" lacks both Langerhans cells granules and melanosomes, yet it is clearly not a keratinocyte. Suggestions have been made that it is related to either Langerhans cells or melanocyte. Recent studies have unequivocally demonstrated that Langerhans cells are independent cells with immune function. They display Fc and C3 receptors on their surface as well as la (immune region associated) antigens.

Lymphoproliferative disorders (LPD) involving lungs: T and B cell subsets within pulmonary infiltrates and in peripheral blood

1984 ◽  
Vol 42 ◽  
pp. 700-701
Author(s):  
Irene Stachura ◽  
Milton H. Dalbow ◽  
Michael J. Niemiec ◽  
Matias Pardo ◽  
Gurmukh Singh ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Lymphoproliferative Disorders ◽  
Mixed Population ◽  
Lymphoid Cells ◽  
Lymphomatoid Granulomatosis ◽  
Cell Type ◽  
Cell Surface Antigens ◽  
Pulmonary Infiltrates ◽  
B Cell Subsets

Lymphoid cells were analyzed within pulmonary infiltrates of six patients with lymphoproliferative disorders involving lungs by immunofluorescence and immunoperoxidase techniques utilizing monoclonal antibodies to cell surface antigens T11 (total T), T4 (inducer/helper T), T8 (cytotoxic/suppressor T) and B1 (B cells) and the antisera against heavy (G,A,M) and light (kappa, lambda) immunoglobulin chains. Three patients had pseudolymphoma, two patients had lymphoma and one patient had lymphomatoid granulomatosis.A mixed population of cells was present in tissue infiltrates from the three patients with pseudolymphoma, IgM-kappa producing cells constituted the main B cell type in one patient. In two patients with lymphoma pattern the infiltrates were composed exclusively of T4+ cells and IgG-lambda B cells predominated slightly in the patient with lymphomatoid granulomatosis.

Nuclear receptors in disease: the oestrogen receptors

2004 ◽  
Vol 40 ◽  
pp. 157-167 ◽  
Author(s):  
Maria Nilsson ◽  
Karin Dahlman-Wright ◽  
Jan-Åke Gustafsson
Keyword(s):  
Nuclear Receptors ◽  
Target Genes ◽  
Receptor Subtype ◽  
Target Tissue ◽  
Oestrogen Receptors ◽  
Nucleotide Polymorphisms ◽  
Cell Type ◽  
Single Nucleotide ◽  
Beneficial Effects ◽  
The Family

For several decades, it has been known that oestrogens are essential for human health. The discovery that there are two oestrogen receptors (ERs), ERalpha and ERbeta, has facilitated our understanding of how the hormone exerts its physiological effects. The ERs belong to the family of ligand-activated nuclear receptors, which act by modulating the expression of target genes. Studies of ER-knockout (ERKO) mice have been instrumental in defining the relevance of a given receptor subtype in a certain tissue. Phenotypes displayed by ERKO mice suggest diseases in which dysfunctional ERs might be involved in aetiology and pathology. Association between single-nucleotide polymorphisms (SNPs) in ER genes and disease have been demonstrated in several cases. Selective ER modulators (SERMs), which are selective with regard to their effects in a certain cell type, already exist. Since oestrogen has effects in many tissues, the goal with a SERM is to provide beneficial effects in one target tissue while avoiding side effects in others. Refined SERMs will, in the future, provide improved therapeutic strategies for existing and novel indications.

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