Alternative Gene Expression in Type I and Type II Cells May Enable further Nuclear Changes during Conjugation of Blepharisma japonicum

We used microarray analysis with Affymetrix rat chips to determine gene expression profiles of freshly isolated rat type I (TI) and TII cells and cultured TII cells. Our goals were 1) to describe molecular phenotypic “fingerprints” of TI and TII cells, 2) to gain insight into possible functional differences between the two cell types through differentially expressed genes, 3) to identify genes that might indicate potential functions of TI cells, since so little is known about this cell type, and 4) to ascertain the similarities and differences in gene expression between cultured TII cells and freshly isolated TI cells. For these experiments, we used preparations of isolated TI and TII cells that contained <2% cross-contamination. With a false discovery rate of 1%, 601 genes demonstrated over twofold different expression between TI and TII cells. Those genes with very high levels of differential expression may be useful as markers of cell phenotype and in generating novel hypotheses about functions of TI and TII cells. We found similar numbers of differentially expressed genes between freshly isolated TI or TII cells and cultured TII cells (698, 637 genes) and freshly isolated TI and TII cells (601 genes). Tests of sameness/difference including cluster dendrograms and log/log identity plots indicated major differences between the phenotypes of freshly isolated TI cell and cultured type II cell populations. The latter results suggest that experiments with TII cells cultured under these conditions should be interpreted with caution with respect to biological relevance to TI or TII cells.

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Ultrastructure of meiosis-inducing (heterotypic) and non-inducing (homotypic) cell unions in conjugation of Blepharisma

Journal of Cell Science ◽

10.1242/jcs.32.1.31 ◽

1978 ◽

Vol 32 (1) ◽

pp. 31-43

Author(s):

C. Bedini ◽

A. Lanfranchi ◽

R. Nobili ◽

A. Miyake

Keyword(s):

Ultrastructural Level ◽

Cell Junctions ◽

Type I ◽

Type Ii ◽

Initiation Mechanism ◽

Blepharisma Japonicum ◽

Nuclear Changes ◽

Cytoplasmic Bridges ◽

Multicellular Organisms ◽

20 Nm

Cells of mating types I and II of Blepharisma japonicum interact with each other and unite in heterotypic (type I-type II) or homotypic (type I-type I, type II-type II) pairs. Heterotypic pairs undergo meiosis and other nuclear changes of conjugation, while homotypic pairs remain united for days without the nuclear changes taking place. We compared cell unions of these two kinds of pairs at the ultrastructural level. In the homotypic union, cell membranes are closely juxtaposed, separated by a distance of about 20 nm. This arrangement is interrupted in some places by vacuoles and small cytoplasmic bridges. Saccule-like structures tend to be more abundant near the united surfaces. Microtubules running at right or slightly obtuse angles with the cell surface (PACM microtubules) are characteristically present at the united region of cells. These structures are very similar to those observed in earlier stages of the heterotypic union. However, in homotypic pairs, cells unite only at the anterior half of the peristome, while in heterotypic pairs cells unite also at the posterior half of the peristome, where the cell membrane totally disappears in later stages. PACM microtubules persist for at least 18 h in homotypic unions, while they disappear within a few hours in heterotypic unions. These differences between the two kinds of cell union are discussed in relation to the initiation mechanism of meiosis and other nuclear changes of conjugation. Similarities between homotypic union and cell junctions in multicellular organisms are also discussed.

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Gamones and mating types in the genus Blepharisma and their possible taxonomic application

Genetics Research ◽

10.1017/s0016672300016451 ◽

1976 ◽

Vol 27 (2) ◽

pp. 267-275 ◽

Cited By ~ 16

Author(s):

Akio Miyake ◽

Lea K. Bleyman

Keyword(s):

The Other ◽

Type I ◽

Type Ii Cells ◽

Mating Types ◽

Type Ii ◽

Type I Cells ◽

Blepharisma Japonicum ◽

Union Type ◽

I Cells

SUMMARYMating types I and II of Blepharisma japonicum v. intermedium excrete gamones 1 (blepharmone J) and 2 (blepharismone) respectively. The gamone of one type transforms cells of the other type so that they can conjugate with each other. We found that three other species, B. americanum, B. musculus and B. stoltei, have two types of cells homologous to those in B. japonicum; one (type II) excretes a factor which has the same activity as gamone 2 of B. japonicum, the other (type I) responds to this gamone by cell union. Type I cells of these species also excrete a gamone which induces pairs in type II cells of particular strains. Complementarity for mating is observed in some combinations of the two types.These results indicate that each of the four species has at least one pair of complementary mating types, I and II, with the gamones of the type II's being the same molecule, blepharismone, while gamones of type I's are species- or syngen-specific blepharmone. These generic and specific gamones can be utilized to clarify existing taxonomic and evolutionary questions in the genus Blepharisma.

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A chimeric type II/type I interleukin-1 receptor can mediate interleukin-1 induction of gene expression in T cells

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)82225-6 ◽

1993 ◽

Vol 268 (14) ◽

pp. 10490-10494

Author(s):

A. Heguy ◽

C.T. Baldari ◽

S. Censini ◽

P. Ghiara ◽

J.L. Telford

Keyword(s):

Gene Expression ◽

T Cells ◽

Interleukin 1 ◽

Type I ◽

Type Ii

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CD95 death-inducing signaling complex formation and internalization occur in lipid rafts of type I and type II cells

European Journal of Immunology ◽

10.1002/eji.200324786 ◽

2004 ◽

Vol 34 (7) ◽

pp. 1930-1940 ◽

Cited By ~ 77

Author(s):

Adriana Eramo ◽

Massimo Sargiacomo ◽

Lucia Ricci-Vitiani ◽

Matilde Todaro ◽

Giorgio Stassi ◽

...

Keyword(s):

Complex Formation ◽

Lipid Rafts ◽

Type I ◽

Type Ii Cells ◽

Type Ii ◽

Signaling Complex

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The Roles Potassium Currents Play in Regulating the Electrical Activity of Ventral Cochlear Nucleus Neurons

Journal of Neurophysiology ◽

10.1152/jn.00127.2002 ◽

2003 ◽

Vol 89 (6) ◽

pp. 3097-3113 ◽

Cited By ~ 180

Author(s):

Jason S. Rothman ◽

Paul B. Manis

Keyword(s):

Cochlear Nucleus ◽

Auditory Nerve ◽

Threshold Current ◽

Repetitive Firing ◽

Resting Membrane Potential ◽

Type I ◽

Type Ii Cells ◽

Type Ii ◽

Ventral Cochlear Nucleus ◽

Discharge Patterns

Using kinetic data from three different K+ currents in acutely isolated neurons, a single electrical compartment representing the soma of a ventral cochlear nucleus (VCN) neuron was created. The K+ currents include a fast transient current ( IA), a slow-inactivating low-threshold current ( ILT), and a noninactivating high-threshold current ( IHT). The model also includes a fast-inactivating Na+ current, a hyperpolarization-activated cation current ( Ih), and 1–50 auditory nerve synapses. With this model, the role IA, ILT, and IHT play in shaping the discharge patterns of VCN cells is explored. Simulation results indicate that IHT mainly functions to repolarize the membrane during an action potential, and IA functions to modulate the rate of repetitive firing. ILT is found to be responsible for the phasic discharge pattern observed in Type II cells (bushy cells). However, by adjusting the strength of ILT, both phasic and regular discharge patterns are observed, demonstrating that a critical level of ILT is necessary to produce the Type II response. Simulated Type II cells have a significantly faster membrane time constant in comparison to Type I cells (stellate cells) and are therefore better suited to preserve temporal information in their auditory nerve inputs by acting as precise coincidence detectors and having a short refractory period. Finally, we demonstrate that modulation of Ih, which changes the resting membrane potential, is a more effective means of modulating the activation level of ILT than simply modulating ILT itself. This result may explain why ILT and Ih are often coexpressed throughout the nervous system.

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Disparate cytokine regulation of ICAM-1 in rat alveolar epithelial cells and pulmonary endothelial cells in vitro

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1995.269.1.l127 ◽

1995 ◽

Vol 269 (1) ◽

pp. L127-L135 ◽

Cited By ~ 5

Author(s):

W. W. Barton ◽

S. Wilcoxen ◽

P. J. Christensen ◽

R. Paine

Keyword(s):

Endothelial Cells ◽

Epithelial Cells ◽

Inflammatory Cytokines ◽

Alveolar Epithelial Cells ◽

Normal Lung ◽

Type I ◽

Type Ii Cells ◽

Type Ii ◽

Alveolar Epithelial

Intercellular adhesion molecule-1 (ICAM-1) is expressed at high levels on type I alveolar epithelial cells in the normal lung and is induced in vitro as type II cells spread in primary culture. In contrast, in most nonhematopoetic cells ICAM-1 expression is induced in response to inflammatory cytokines. We have formed the hypothesis that the signals that control ICAM-1 expression in alveolar epithelial cells are fundamentally different from those controlling expression in most other cells. To test this hypothesis, we have investigated the influence of inflammatory cytokines on ICAM-1 expression in isolated type II cells that have spread in culture and compared this response to that of rat pulmonary artery endothelial cells (RPAEC). ICAM-1 protein, determined both by a cell-based enzyme-linked immunosorbent assay and by Western blot analysis, and mRNA were minimally expressed in unstimulated RPAEC but were significantly induced in a time- and dose-dependent manner by treatment with tumor necrosis factor-alpha, interleukin-1 beta, or interferon-gamma. In contrast, these cytokines did not influence the constitutive high level ICAM-1 protein expression in alveolar epithelial cells and only minimally affected steady-state mRNA levels. ICAM-1 mRNA half-life, measured in the presence of actinomycin D, was relatively long at 7 h in alveolar epithelial cells and 4 h in RPAEC. The striking lack of response of ICAM-1 expression by alveolar epithelial cells to inflammatory cytokines is in contrast to virtually all other epithelial cells studied to date and supports the hypothesis that ICAM-1 expression by these cells is a function of cellular differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

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Sulfation of extracellular matrices modifies responses of alveolar type II cells to fibroblast growth factors

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1996.271.5.l688 ◽

1996 ◽

Vol 271 (5) ◽

pp. L688-L697 ◽

Cited By ~ 9

Author(s):

P. L. Sannes ◽

J. Khosla ◽

P. W. Cheng

Keyword(s):

Growth Factors ◽

Biological Significance ◽

Alveolar Type ◽

Type I ◽

Type Ii Cells ◽

Type Ii ◽

Fibroblast Growth ◽

Alveolar Type Ii Cells ◽

Proliferation And Differentiation ◽

Type Ii Cell

The pulmonary alveolar basement membrane (BM) associated with alveolar type II cells has been shown to be significantly less sulfated than that of type I cells. To examine the biological significance of this observation, we measured the incorporation of 5-bromodeoxyuridine (BrdU) as an indicator of DNA synthesis in isolated rat type II cells cultured for 72-120 h on substrata that were naturally sulfated, not sulfated, or chemically desulfated in serum-free, hormonally defined media, with and without selected growth factors. The percentage of cells incorporating BrdU was significantly elevated by desulfated chondroitin sulfate in the presence of fibroblast growth factor-2 (FGF-2 or basic FGF) and depressed by heparin in the presence of either FGF-1 or acidic FGF or FGF-2. This depressive effect was lost by removing sulfate from the heparin. Some responses were dependent on the period of time in culture and concentration and molecular weight of the substrata. These observations support the notion that sulfation per se of certain components of BM is a key determinant of type II cell responses to select growth factors that may define patterns of proliferation and differentiation.

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