Search results for "Differentiation"
showing 10 items of 1605 documents
Genetic and molecular analysis of six tumor suppressor genes in Drosophila melanogaster
1990
Six Drosophila melanogaster tumor suppressor genes causing malignant or benign tumors in specific cell types are described. The wild-type alleles of these genes are instrumental in the differentiation of particular cell types. In the homozygous state, recessive mutations in the genes interrupt the differentiation of the cells and thus cause their uncontrolled, autonomous, lethal proliferation. The tumors show all major characteristics of malignant and benign neoplastic growth. Genomic sequences of four of the genes have been identified and are currently being characterized. ImagesFIGURE 1.FIGURE 2.FIGURE 2.
MicroRNAs and cellular phenotypy.
2010
This Essay explores the notion that specialized cells have unique vulnerabilities to environmental contingencies that microRNAs help to counteract. Given the ease with which new microRNAs evolve, they may serve as ideal facilitators for the emergence of new cell types.
Complementation among developmental mutants in Aspergillus nidulans.
1973
In heterokaryons between pairs of aconidial mutants of Aspergillus nidulans one of the component strains usually shows a striking prevalance in the contribution to the conidial crop. By assuming that the prevailing strain is blocked earlier and the succumbent one later in the process of differentiation, a series of mutations can be arranged in a consistent order. Some mutant strains do not fit the scheme exactly but show a general tendency to be succumbent to “early” mutants and prevalent over the “late” ones. A criterion for arraying genes involved in differentiation according to the order of their physiological action is proposed.
Transcriptomic Signature of Trophoblast Differentiation in a Human Embryonic Stem Cell Model1
2011
Identification of genes involved in trophoblast differentiation is of great interest in understanding cellular and molecular mechanisms involved in placental development and is relevant clinically to fetal development, fertility, and maternal health. Herein, we investigated differentiation of human embryonic stem cells (hESCs) down the trophoblast lineage by culture with bone morphogenetic protein 4 (BMP4) over a 10-day period. Within 2 days, the stemness markers POU5F1 and NANOG were markedly down-regulated, followed temporally by up-regulation of the CDX2, KRT7, HLA-G, ID2, CGA, and CGB trophoblast markers. To understand, on a global scale, changes in the transcriptome during the differen…
The genetic structure of Drosophila subobscura populations from the islands of Majorca and Minorca (Balearic Islands, Spain) based on allozymes and m…
1999
The genetic structure of seven populations of Drosophila subobscura from different locations on Majorca and Minorca (Balearic Islands, Spain) was studied using two types of markers: allozyme and mitochondrial DNA restriction analyses. Both markers showed congruent results. In the allozyme data, when the Acph-1 locus was excluded from the joint FST statistics, only three out of 21 comparisons were statistically significant, lending support to the hypothesis of low genetic differentiation. The mtDNA restriction analyses showed two haplotypes at a high frequency (more than 40% each), irrespective of the location considered, and a number of endemic haplotypes at very low frequencies (not higher…
Tubulin gene expression persists during all changes in microtubular arrays related to cell shaping in growing barley leaves
1998
Summary Levels of α-tubulin RNA were determined in consecutive leaf segments taken along young, growing barley leaves by Northern blotting. The leaves exhibited a developmental gradient typical of graminaceous species ranging from a meristem at the base to fully differentiated cells at the tip. The objective was to ascertain whether or not high steady-state tubulin RNA levels accompany characteristic changes in microtubular arrays known to occur during cell division and differentiation. Of particular interest was the differentiation zone comprising a succession of well defined changes in microtubular arrays that appear to be involved in the control of cell shaping. High steady-state levels …
A comparison of two indirect methods for estimating average levels of gene flow using microsatellite data.
1999
We compare the performance of Nm estimates based on FST and RST obtained from microsatellite data using simulations of the stepwise mutation model with range constraints in allele size classes. The results of the simulations suggest that the use of microsatellite loci can lead to serious overestimations of Nm, particularly when population sizes are large (N5000) and range constraints are high (K20). The simulations also indicate that, when population sizes are small (N/= 500) and migration rates are moderate (Nm approximately 2), violations to the assumption used to derive the Nm estimators lead to biased results. Under ideal conditions, i.e. large sample sizes (ns/= 50) and many loci (nl/=…
Simultaneous Aurora-A/STK15 overexpression and centrosome amplification induce chromosomal instability in tumour cells with a MIN phenotype
2007
Abstract Background Genetic instability is a hallmark of tumours and preneoplastic lesions. The predominant form of genome instability in human cancer is chromosome instability (CIN). CIN is characterized by chromosomal aberrations, gains or losses of whole chromosomes (aneuploidy), and it is often associated with centrosome amplification. Centrosomes control cell division by forming a bipolar mitotic spindle and play an essential role in the maintenance of chromosomal stability. However, whether centrosome amplification could directly cause aneuploidy is not fully established. Also, alterations in genes required for mitotic progression could be involved in CIN. A major candidate is represe…
Rare earth elements in apatite as a monitor of magmatic and metasomatic processes: The Ilímaussaq complex, South Greenland
2015
Abstract Textural and compositional variations of apatite from the plutonic Ilimaussaq complex in South Greenland and its surrounding country rocks track magmatic and metasomatic processes. Detailed back-scattered electron (BSE) imaging reveals various types of apatite textures including (i) growth zonation (concentric, oscillatory as well as sector zonation) formed during magmatic differentiation, (ii) resorption and overgrowth textures due to fluid/melt induced metasomatic overprint of precursor apatite and (iii) replacement textures indicating the destabilization of apatite in favor of monazite. In the least evolved rocks of the Ilimaussaq complex, apatite incorporates rare earth element…
Evidences of magma mixing in the "Daly gap" of the alkaline suites: a case study from the enclaves of Pantelleria (Italy)
2006
The island of Pantelleria consists of trachytes, pantellerites and minor mildly alkaline basalts. Rocks of intermediate composition (falling in the so-called ‘Daly Gap’) such as mugearites, benmoreites and mafic trachytes occur only in the form of enclaves in trachytes and pantellerites inside the main caldera of the island (Caldera ‘Cinque Denti’), which collapsed during the ‘Green Tuff ’ ignimbrite eruption at 50 ka. The enclaves include volcanic, subvolcanic and intrusive rock types. The enclaves in host trachyte contain traces of glass; devitrified glass occurs within enclaves in host pantellerites. Minerals in the enclaves show regular compositional variations with whole-rock silica co…