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At least 127 records · Page 7Linked to original sources
PubMed1988

Cell lineage analysis of lens epithelial cells induced to differentiate into fibres.

In explant cultures, lens epithelial cells grown in unsupplemented medium retain a morphology and packing arrangement similar to that found in the lens in vivo. In this culture system the epithelial cells can be induced to differentiate into fibres by the addition of retina conditioned medium (RCM). RCM also stimulates cell division. In order to trace the fibre cell lineage and to examine the relationship between cell division and fibre differentiation, single epithelial cells in explants from neonatal rat lenses were labelled with fluorescein-isothiocyanate-dextran. Explants were sub-divided into nine squares and one cell per square was injected with fluorescent label via a microcapillary. By marking the positions of labelled cells at 24-hr intervals for 6 days it was shown that most of the epithelial cells moved laterally within the explant. On average, cells in control explants moved about 20 microns day-1. Cells did not move in any particular direction within the explants and often changed direction. RCM stimulated a dramatic increase in migratory activity. There was about a four-fold increase in migratory activity in the first 24-hr interval, then, even with continued exposure to RCM, this activity quickly dropped over the next 2 days to the same levels as found in controls. As in controls, the cells moved in no particular direction and often changed direction. The observation that RCM stimulates cell migration in this explant system raises the possibility of an important role for active cell migration in the lens in situ. After 6 days culture the dimensions of labelled cells were measured using an image analyser. The areas of cells in controls fell within a narrow range from about 60- to 200 microns2. In contrast, explants grown in RCM had a wide range of cell areas from about 120- to 1500 microns2 and a large proportion of the cells showed some degree of elongation. In explants grown in RCM, 27.3% of labelled cells divided and half of these divisions were during the first 24 hr of culture. Overall there were about 9% more divisions recorded in RCM-treated than in control explants. An analysis of sizes of cells after 6 days of culture showed that whether or not cells divided after addition of RCM they showed very similar frequencies of cell sizes. Therefore, proliferating cells in the explants appear to be as capable of elongating and differentiating into fibres as the non-proliferating cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Experimental analyses of the migration and cell lineage of avian neural crest cells.

Neural crest cells migrate extensively during embryonic development and give rise to numerous and varied derivatives. Two important and unresolved questions are: what controls the migration and differentiation of these cells? This review summarizes recent experiments that address these issues. Specifically, this overview describes the pathways of neural crest cell migration, the functional importance of interactions between neural crest cells and the extracellular matrix for their movement, and studies on neural crest cell lineage in vivo by labelling individual precursor cells.

Animals↗
PubMed2004

Magnifying stem cell lineages: the stop-EGFP mouse.

Cell fate mapping techniques which can label clonal cell lineages are of importance because they allow one to investigate the distribution and types of daughter cells arising from single precursor cells. Thus, the potential of precursor cells to generate various types of descendent cells can be studied at the single-cell level. The stop-EGFP transgenic mouse carries a premature stop codon-containing enhanced green fluorescent protein (EGFP) gene as a target gene for mutations. A cell having undergone a mutation at the premature stop codon and its descendant cell lineage will express EGFP, thus a clonal cell lineage can be traced in vivo using a fluorescent microscope. Using the stop-EGFP mouse, stem cell clonal lineages in the mouse dorsal epidermis can be investigated in vivo and repeated analyses of the same cell lineages can be performed over time. In vivo imaging studies possible with the stop-EGFP mouse provide new insights into the structure of epidermal proliferative units (EPUs). The stop-EGFP system provides a novel tool for investigating clonal cell lineages in developmental studies as well as in stem cell biology.

Animals↗
PubMed1987

Expression of cell type-specific markers during pancreatic development in the mouse: implications for pancreatic cell lineages.

The islet cells of the mammalian pancreas are comprised of four different endocrine cell types, each containing a specific hormone. Islet cells also contain two enzymes of the catecholamine biosynthetic pathway : tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC). The cell lineage relationships of these different cell types have not been examined and it is not known whether, during development, they originate from the same or from different precursor populations. In this study we used immunocytochemical procedures to determine whether developing pancreatic cells express markers common to endocrine and exocrine cell types. We found that acinar cell precursors express AADC prior to the appearance of an exocrine marker and that the expression of AADC in acinar cells persists throughout embryogenesis to the first month of postnatal life. At this time, acinar cells do not contain AADC. We also found that exocrine cells containing AADC never express other islet-cell markers. These findings suggest that while acinar and islet cells both arise from precursor cells containing AADC, these progenitor cells do not express a combined endocrine-exocrine phenotype.

Aging↗
PubMed1993

A novel monoclonal antibody (FUN-1) identifies an activation antigen in cells of the B-cell lineage and Reed-Sternberg cells.

The characterization of a new monoclonal antibody (MoAb) recognizing a human B-cell activation antigen, designated FUN-1, is described in this paper. Immunoprecipitation revealed that FUN-1 recognizes an antigen with a molecular weight (MW) of 75kD. FUN-1 reacts with pokeweed mitogen-activated B lymphocytes and monocytes of peripheral blood, but not with unstimulated lymphocytes or granulocytes. It also reacts with large lymphoid cells in germinal centres, Epstein-Barr virus-transformed B cell lines, large B-cell lymphomas, Ki-1-positive anaplastic large-cell lymphomas, and Reed-Sternberg cells of Hodgkin's disease, but not with Concanavalin A-activated T cells, acute lymphoblastic leukaemias, T-cell lymphomas, or low-grade B-cell leukaemias. These findings indicate that FUN-1 recognizes a previously unreported B-cell activation antigen. This MoAb appears to be useful for the study of maturation and differentiation in the B-cell lineage as well as for the immunohistochemical diagnosis of B-cell lymphomas and Hodgkin's disease.

Animals↗
PubMed2005

The Arabidopsis R2R3 MYB proteins FOUR LIPS and MYB88 restrict divisions late in the stomatal cell lineage.

The two guard cells of a stoma are produced by a single symmetric division just before terminal differentiation. Recessive mutations in the FOUR LIPS (FLP) gene abnormally induce at least four guard cells in contact with one another. These pattern defects result from a persistence of precursor cell identity that leads to extra symmetric divisions at the end of the cell lineage. FLP is likely to be required for the correct timing of the transition from cell cycling to terminal differentiation. FLP encodes a two-repeat (R2R3) MYB protein whose expression accumulates just before the symmetric division. A paralogous gene, MYB88, overlaps with FLP function in generating normal stomatal patterning. Plants homozygous for mutations in both genes exhibit more severe defects than flp alone, and transformation of flp plants with a genomic MYB88 construct restores a wild-type phenotype. Both genes compose a distinct and relatively basal clade of atypical R2R3 MYB proteins that possess an unusual pattern of amino acid substitutions in their putative DNA binding domains. Our results suggest that two related transcription factors jointly restrict divisions late in the Arabidopsis thaliana stomatal cell lineage.

Amino Acid Substitution↗
PubMed1993

Characterization of a macrophage lineage cell colony-stimulating factor produced by thymic myoid cells.

Thymic myoid cells produced macrophage lineage cell stimulatory factors. Activities were separated into two factors on DEAE-Sepharose CL-6B chromatography: one eluted at lower concentrations of NaCl and the other at higher concentrations of NaCl. The latter fraction was purified to homogeneity with an apparent molecular weight of 100,000. This factor stimulated the growth of macrophage-lineage cells from the bone marrow, but not that of granulocytes, megakaryocytes or erythroblasts. The 100,000 MW factor was able to induce Ia antigens on proliferating bone marrow cells. These results suggest that myoid cell-derived 100,000 MW factor plays significant roles in the generation of Ia-positive macrophage lineage cells which are important for T-cell development in the thymus.

Animals↗
PubMed1981

Mutations that lead to reiterations in the cell lineages of C. elegans.

Cells in the nematode Caenorhabditis elegans arise from invariant cell lineages. Mutations in two genes, unc-86 and lin-4, alter multiple and mutually exclusive sets of these lineages. In these mutants, particular cells repeat division patterns normally associated with their parental or grandparental progenitors. The effects of unc-86 are highly specific, altering in equivalent ways the lineages of three post-embryonic neuroblasts that in the wild-type undergo similar division patterns. The effects of lin-4 are more varied, resulting in a number of types of lineage reiterations as well as in supernumerary molts and the continued synthesis of larval-specific cuticle. The reiteration of a given cell division or pattern of cell divisions leads to the repeated generation of cells indistinguishable (by both light and electron microscopy) from those produced after the same division or pattern of cell divisions in the wild-type. This correlation between lineage history and cell fate suggests that in C. elegans a particular sequence of cell divisions may be necessary for the generation of a particular cell type. Reiterative lineages, often referred to as stem cell lineages, may be basic to the development of nematodes and other organisms. We suggest that the wild-type unc-86 and lin-4 genes act to modify latent reiterative cell lineages, which are revealed when the activity of one of these genes is eliminated.

Animals↗
PubMed2004

Single cell lineage and regionalization of cell populations during Medaka neurulation.

To study the movement of individual cells and development of cell grouping during neurogenesis, we labeled single cells in early Medaka gastrula at stage 13 [13 hours post-fertilization (hpf)] with a fluorescent vital dye, and analyzed cells and their descendants using time-lapse live recording up to stage 24 (44 hpf). At stage 13, all future neural cells were located in a dorsal 140 degrees sector of the embryo, and migrated toward the vegetal pole; but during stage 15 to 16, they converged towards the midline. Cells that contributed to later neural subdivisions initially formed overlapping populations, but after stage 16+ they formed non-overlapping cell groups having characteristics of tissue 'compartments', preceding development of morphologically distinct neural subdivisions. In early retinal development, a single compartment for future retinal cells was formed superficial to telencephalic and diencephalic compartments, but it was split into left and right eye components at stage 17 in parallel with anterodorsal movement of the diencephalic compartment. At stage 16+, when these compartments were established, Pax6 expression initiated, but only in the laterally located subpopulation of the retina precursor. These observations revise the current view of bilateral retinal development. Continuous live recording of labeled single precursor cells and computer graphics-assisted data analysis, which are presented for the first time in this study, provide excellent means with which to analyze essential cellular processes in organogenesis.

Animals↗
PubMed2006

Concise review: epigenetic mechanisms contribute to pluripotency and cell lineage determination of embryonic stem cells.

Epigenetic mechanisms, such as histone modifications and DNA methylation, have been shown to play a key role in the regulation of gene transcription. Results of recent studies indicate that a novel "bivalent" chromatin structure marks key developmental genes in embryonic stem cells (ESCs), wherein a number of untranscribed lineage-control genes, such as Sox1, Nkx2-2, Msx1, Irx3, and Pax3, are epigenetically modified with a unique combination of activating and repressive histone modifications that prime them for potential activation (or repression) upon cell lineage induction and differentiation. However, results of these studies also showed that a subset of lineage-control genes, such as Myf5 and Mash1, were not marked by these histone modifications, suggesting that distinct epigenetic mechanisms might exist for lineage-control genes in ESCs. In this review article, we summarize evidence regarding possible mechanisms that control these unique histone modifications at lineage-control gene loci in ESCs and consider their possible contribution to ESC pluripotency. In addition, we propose a novel "histone modification pulsing" model wherein individual pluripotent stem cells within the inner cell mass of blastocysts undergo transient asynchronous histone modifications at these developmental gene loci, thereby conferring differential responsiveness to environmental cues and morphogenic gradients important for cell lineage determination. Finally, we consider how these rapid histone modification exchanges become progressively more stable as ESCs undergo differentiation and maturation into specialized cell lineages.

Animals↗
PubMed2004

A stop-EGFP transgenic mouse to detect clonal cell lineages generated by mutation.

The investigation of cell lineages and clonal organization in tissues is facilitated by techniques that allow labelling of clonal cell lineages. Here, we describe a novel transgenic mouse that allows clonal cell lineages to be traced in virtually any tissue. A green fluorescent cell lineage is generated by a random mutation at an enhanced green fluorescent protein gene that carries a premature stop codon, ensuring clonality. The transgenic system allows efficient detection of mutations and stem-cell fate mapping in the epidermis using live mice, as well as in the kidney and liver post-mortem. Cell lineages that descended from single epidermal stem cells were found to be capable of generating three adjacent corneocytes using the system, providing evidence for horizontal migration of epidermal cells between epidermal proliferative units (EPUs), in contrast to the classical EPU model. The transgenic mouse system is expected to provide a novel tool for stem-cell lineage studies.

Animals↗
PubMed1985

Early events in insect neurogenesis. II. The role of cell interactions and cell lineage in the determination of neuronal precursor cells.

The insect central nervous system (CNS) is composed of a brain and a chain of segmental ganglia; each hemiganglion contains about 1000 individually identifiable neurons. How is the enormous neuronal diversity and specificity generated? Neurons of a hemiganglion largely arise during embryogenesis from a stereotyped pattern of individually identified neuronal precursor cells, called neuroblasts (NBs). The transition from ectoderm to individual neurons thus involves two major steps: first, an undifferentiated ectodermal cell sheet produces the stereotyped pattern of 30 NBs per hemisegment; second, each of these NBs contributes a specific family of neuronal progeny to the developing CNS. We have used a laser microbeam to ablate individual cells in the grasshopper embryo in order to study the initial events of neuronal determination. In particular, how does a layer of apparently equivalent ectodermal cells produce a highly stereotyped pattern of unique NBs? Our results suggest the following mechanism for NB determination. (1) Cell interactions between the approximately 150 equivalent ectodermal cells of a hemisegment allow 30 cells to enlarge into NBs. (2) As these young NBs enlarge they inhibit adjacent ectodermal cells from becoming NBs; the adjacent cells then either differentiate into nonneuronal support cells or die. (3) Each NB is assigned a unique identity due to its position of enlargement within the neuroepithelium. (4) The NB then generates its characteristic family of neurons by an invariant cell lineage. Development of the insect CNS depends on cell interactions and positional cues to create a pattern of NBs, and then on cell lineage to restrict the fate of the NB progeny.

Animals↗
PubMed1988

Difference of cell lineage expression of haematopoietic progenitor cells in Philadelphia-positive acute lymphoblastic leukaemia and chronic myelogenous leukaemia.

It is still difficult to clinically distinguish Philadelphia (Ph1)-positive acute lymphoblastic leukaemia (ALL) from Ph1-positive chronic myelogenous leukaemia (CML) in lymphoid crisis. In this study we tried to discriminate between these two disorders by simultaneous analyses of cell morphology and karyotype in single in vitro colonies. We studied three patients with Ph1-positive ALL and four with Ph1-positive CML in various phases of the disease. Bone marrow and peripheral blood cells obtained directly from all seven patients showed abnormal karyotypes including Ph1-chromosomes. Normal karyotypes were found in a small proportion of cells from two ALL patients, but none were found in any from the CML patients. The patients' mononuclear cells (MNCs) were plated at 1-5 x 10(4)/ml in semi-solid medium containing methylcellulose plus phytohaemagglutinin-stimulated leucocyte conditioned medium and erythropoietin. After 9-14 d cultivation, granulocyte-macrophage, erythroid and mixed colonies obtained were used for simultaneous analysis of cell morphology and karyotype. Morphological examination showed that these colonies contained neutrophils, eosinophils, basophils, macrophages and/or erythroblasts in various combinations. No lymphoblast colonies were obtained under the culture conditions used. Cytogenetic examination revealed that all metaphase cells observed in colonies obtained from Ph1-positive ALL patient MNCs had a normal karyotype, whereas those in colonies from Ph1-positive CML patient MNCs had abnormal karyotypes, including Ph1 chromosomes, suggesting that the difference between the two disorders involved a difference in cell lineage. Our results showed that this method was a practicable method for distinguishing Ph1-positive ALL from Ph1-positive CML in lymphoid crisis.

Adolescent↗
PubMed2000

Cell lineage characteristics of human prostatic stromal cells cultured in vitro.

BACKGROUND: An in vitro model of prostatic stromal cells suitable for experimental studies of the pathogenesis of BPH is still lacking. We therefore standardized the isolation, cultivation, and characterization of human prostatic stromal cell lineages. METHODS: Stromal cells were isolated from a surgical specimen of BPH. Using antibodies specific for either epithelial or stromal cells of the human prostate, the isolated cells were morphologically and immunohistochemically characterized. Viability and functional activity were assessed by proliferation assays and stimulation experiments. Gene expression was monitored by RT-PCR. RESULTS: In early passages (P8), cells showed a high purity (>/=98%) for stromal markers; about 60% displayed the characteristics of fibroblasts, and the remaining 40% were classified as smooth muscle cells. In late passages (P20), the proportion of muscle cells declined to 10%. Stimulation experiments including basic fibroblast growth factor (bFGF) resulted in enhanced proliferation, whereas dihydrotestosterone (DHT), estrogen, and flutamide did not influence proliferation. Gene expression studies demonstrated a positive signal for androgen receptor and keratinocyte growth factor (KGF). CONCLUSIONS: Prostatic stromal cells can be propagated several times and show karyotypic stability for up to 18 subculture experiments. The ratio of myoid and fibroblastic cells can be used for standardization of cell cultures with stable characteristics.

Cell Division↗
PubMed2004

Regulation of alphabeta/gammadelta T cell lineage commitment and peripheral T cell responses by Notch/RBP-J signaling.

RBP-J is a key mediator of Notch signaling that regulates a large spectrum of cell fate determinations. To elucidate the functions of Notch signaling in T cell development, we inactivated RBP-J specifically at two stages of T cell development by crossing RBP-J floxed mice with lck-cre or CD4-cre transgenic mice. The loss of RBP-J at an earlier developmental stage resulted in enhanced generation and accelerated emigration of gammadelta T cells, whereas alphabeta T cell development was arrested at the double-negative 3 stage. The loss of RBP-J at a later stage did not affect the absolute number or the production rate of CD4 or CD8-positive mature T cells but enhanced Th1 cell response and reduced CD4(+) T cell proliferation. Our data demonstrated that Notch/RBP-J signaling regulates gammadelta T cell generation and migration, alphabeta T cell maturation, terminal differentiation of CD4(+) T cells into Th1/Th2 cells, and activation of T cells.

Animals↗
PubMed1986

Volume regulation in leukemic and lymphoma cells in children and determination of cell lineage.

Among normal lymphocytes, T cells can readjust their volume rapidly following initial swelling in a hypotonic medium, whereas B cells do not have this ability. Based on this finding, we examined the volume regulation of malignant cells from 40 patients with lymphocytic and nonlymphocytic malignancies. The T lineage cells were able to regulate their volume in response to hypotonic stress, whereas B lineage cells were not able to do so. In contrast to lymphoid lineage cells, nonlymphocytic leukemia cells as well as undifferentiated cells did not show a consistent tendency in their volume regulation. These results showed that the difference in the ability to regulate cell volume in response to hypotonic stress is available as a marker for identifying the cellular lineage of lymphoid malignancies.

Acute Disease↗
PubMed2001

Intrinsic defects in the T-cell lineage results in natural killer T-cell deficiency and the development of diabetes in the nonobese diabetic mouse.

T-cell-mediated autoimmune diabetes in nonobese diabetic (NOD) mice is closely associated with natural killer T (NKT)-cell deficiency. To determine whether intrinsic defects of the T-cell lineage contribute to the pathogenesis of the disease and NKT cell deficiency, we reconstituted the T-cell compartment in NOD.scid or BALB.scid mice with T-cells from NOD, nonobese diabetes-resistant (NOR), or AKR thymic precursor cells and examined the development of the NKT cell population. NKT cells developed well from AKR thymic precursor cells but not from other precursor cells in both recipient strains. Insulitis and diabetes developed only in the NOD.scid recipients of NOD or NOR precursor cells. When thymic precursor cells of beta2-microglobulin gene-deficient AKR mice, which have a deficient NKT population, were introduced into NOD.scid recipients, both CD4(+) and CD8(+) T-cell populations developed and the recipient mice developed insulitis and diabetes. We conclude that NKT cells originate from a T-cell-committed thymic precursor population and that the deficiency in the NKT cell population in NOD mice results from intrinsic defects within the T-cell lineage and plays a major role in the development of autoimmune diabetes in the presence of both the NOD thymus and antigen-presenting cells.

Animals↗