Repetitive arrays containing a housekeeping gene have altered polytene chromosome morphology in Drosophila

Chromosoma ◽  
1998 ◽  
Vol 107 (2) ◽  
pp. 96-104 ◽  
Author(s):  
Denise V. Clark ◽  
Joy F. Sabl ◽  
Steven Henikoff
Keyword(s):  
Polytene Chromosome ◽  
Housekeeping Gene ◽  
Chromosome Morphology

On an Application of the Metallurgical Stage to Chromosome Morphology

1967 ◽  
Vol 25 ◽  
pp. 28-29
Author(s):  
Godfrey C. Hoskins
Keyword(s):  
Human Chromosome ◽  
Electron Micrographs ◽  
Chromosome Morphology ◽  
Electron Optics ◽  
Electron Micrograph ◽  
Photographic Evidence ◽  
Sophisticated Equipment ◽  
Periodic Arrangement

The first serious electron microscooic studies of chromosomes accompanied by pictures were by I. Elvers in 1941 and 1943. His prodigious study, from the manufacture of micronets to the development of procedures for interpreting electron micrographs has gone all but unnoticed. The application of todays sophisticated equipment confirms many of the findings he gleaned from interpretation of images distorted by the electron optics of that time. In his figure 18 he notes periodic arrangement of pepsin sensitive “prickles” now called secondary fibers. In his figure 66 precise regularity of arrangement of these fibers can be seen. In his figure 22 he reproduces Siegbahn's first stereoscopic electron micrograph of chromosomes.The two stereoscopic pairs of electron micrographs of a human chromosome presented here were taken with a metallurgical stage on a Phillips EM200. These views are interpreted as providing photographic evidence that primary fibers (1°F) about 1,200Å thick are surrounded by secondary fibers (2°F) arranged in regular intervals of about 2,800Å in this metanhase human chromosome. At the telomere the primary fibers bend back on themselves and entwine through the center of each of each chromatid. The secondary fibers are seen to continue to surround primary fibers at telomeres. Thus at telomeres, secondary fibers present a surface not unlike that of the side of the chromosome, and no more susceptible to the addition of broken elements from other chromosomes.

scholarly journals Assessment of common housekeeping genes as reference for gene expression studies using RT-qPCR in mouse choroid plexus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kim Hoa Ho ◽  
Annarita Patrizi
Keyword(s):  
Gene Expression ◽  
Choroid Plexus ◽  
Sensory Deprivation ◽  
Housekeeping Genes ◽  
Housekeeping Gene ◽  
Experimental Conditions ◽  
Brain Repair ◽  
Expression Studies ◽  
Testing Algorithms ◽  
Gene Expression Studies

AbstractChoroid plexus (ChP), a vascularized secretory epithelium located in all brain ventricles, plays critical roles in development, homeostasis and brain repair. Reverse transcription quantitative real-time PCR (RT-qPCR) is a popular and useful technique for measuring gene expression changes and also widely used in ChP studies. However, the reliability of RT-qPCR data is strongly dependent on the choice of reference genes, which are supposed to be stable across all samples. In this study, we validated the expression of 12 well established housekeeping genes in ChP in 2 independent experimental paradigms by using popular stability testing algorithms: BestKeeper, DeltaCq, geNorm and NormFinder. Rer1 and Rpl13a were identified as the most stable genes throughout mouse ChP development, while Hprt1 and Rpl27 were the most stable genes across conditions in a mouse sensory deprivation experiment. In addition, Rpl13a, Rpl27 and Tbp were mutually among the top five most stable genes in both experiments. Normalisation of Ttr and Otx2 expression levels using different housekeeping gene combinations demonstrated the profound effect of reference gene choice on target gene expression. Our study emphasized the importance of validating and selecting stable housekeeping genes under specific experimental conditions.

scholarly journals The usefulness of competitive PCR: airway gene expression of IL-5, IL-4, IL-4δ2, IL-2, and IFNγ in asthma

Thorax ◽  
2001 ◽  
Vol 56 (7) ◽  
pp. 541-548
Author(s):  
E M Glare ◽  
M Divjak ◽  
M J Bailey ◽  
E H Walters
Keyword(s):  
Gene Expression ◽  
Inhaled Corticosteroids ◽  
In Situ Hybridisation ◽  
Housekeeping Gene ◽  
Cross Sectional Study ◽  
Mrna Levels ◽  
Competitive Pcr ◽  
Cross Sectional ◽  
Steroid Use ◽  
Biopsy Specimens

BACKGROUNDAsthma has been described as an eosinophilic bronchitis driven by interleukin(IL)-4 and IL-5. The quantification of cytokine mRNA levels in airway samples has been confounded by housekeeping gene expression which differs between and within asthmatics and controls.METHODSThe usefulness of competitive reverse transcriptase-polymerase chain reaction (RT-PCR) that is independent of housekeeping gene expression for quantitating the mRNA for interferon (IFN)γ, IL-2, IL-5, IL-4 and its receptor antagonist encoding splicing variant IL-4δ2 was determined in a cross sectional study of 45 normal control subjects and 111 with asthma.RESULTSAtopic controls and atopic asthmatic subjects expressed more IL-5 than non-atopic controls (p<0.02) in bronchoalveolar lavage (BAL) cells, but not in biopsy specimens. IL-5 mRNA expression in BAL cells from asthmatic subjects using inhaled corticosteroids (ICS) was significantly lower than those not receiving ICS (p=0.04). IL-2 mRNA levels differed with steroid use in biopsy specimens but not in BAL cells. IFNγ, IL-4, and IL-4δ2 mRNA levels did not differ between any groups and were not affected by steroid use. IL-4 and IL-4δ2 mRNA levels were positively correlated (p<0.0001), suggesting coordinated transcription.CONCLUSIONSWhile the signal differentiation of competitive PCR in asthma may rival that of in situ hybridisation and immunohistochemistry, the method is expensive and wasteful of material.

scholarly journals Assessment of the Telomere Length and Its Effect on the Symptomatology of Parkinson’s Disease

Antioxidants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 137
Author(s):  
Tina Levstek ◽  
Sara Redenšek ◽  
Maja Trošt ◽  
Vita Dolžan ◽  
Katarina Trebušak Podkrajšek
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Telomere Length ◽  
Repetitive Sequences ◽  
Housekeeping Gene ◽  
Cellular Aging ◽  
Brain Diseases ◽  
Motor Complications ◽  
Telomere Attrition ◽  
Significant Difference

Telomeres, which are repetitive sequences that cap the end of the chromosomes, shorten with each cell division. Besides cellular aging, there are several other factors that influence telomere length (TL), in particular, oxidative stress and inflammation, which play an important role in the pathogenesis of neurodegenerative brain diseases including Parkinson’s disease (PD). So far, the majority of studies have not demonstrated a significant difference in TL between PD patients and healthy individuals. However, studies investigating the effect of TL on the symptomatology and disease progression of PD are scarce, and thus, warranted. We analyzed TL of peripheral blood cells in a sample of 204 PD patients without concomitant autoimmune diseases and analyzed its association with several PD related phenotypes. Monochrome multiplex quantitative PCR (mmqPCR) was used to determine relative TL given as a ratio of the amount of DNA between the telomere and albumin as the housekeeping gene. We found a significant difference in the relative TL between PD patients with and without dementia, where shorter TL presented higher risk for dementia (p = 0.024). However, the correlation was not significant after adjustment for clinical factors (p = 0.509). We found no correlations between TLs and the dose of dopaminergic therapy when the analysis was adjusted for genetic variability in inflammatory or oxidative factors. In addition, TL influenced time to onset of motor complications after levodopa treatment initiation (p = 0.0134), but the association did not remain significant after adjustment for age at inclusion and disease duration (p = 0.0781). Based on the results of our study we conclude that TL contributes to certain PD-related phenotypes, although it may not have a major role in directing the course of the disease. Nevertheless, this expends currently limited knowledge regarding the association of the telomere attrition and the disease severity or motor complications in Parkinson’s disease.

scholarly journals Impaired Expression of Cytoplasmic Actins Leads to Chromosomal Instability of MDA-MB-231 Basal-Like Mammary Gland Cancer Cell Line

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2151
Author(s):  
Vera Dugina ◽  
Galina Shagieva ◽  
Mariya Novikova ◽  
Svetlana Lavrushkina ◽  
Olga Sokova ◽  
...  
Keyword(s):  
Cell Line ◽  
Chromosomal Instability ◽  
Cell Transformation ◽  
Cancer Cell Line ◽  
Neoplastic Cell ◽  
Chromosome Morphology ◽  
Human Carcinoma ◽  
Actin Isoforms ◽  
Cytoplasmic Actin ◽  
Neoplastic Cell Transformation

We have shown previously that two cytoplasmic actin isoforms play different roles in neoplastic cell transformation. Namely, β-cytoplasmic actin acts as a tumor suppressor, whereas γ-cytoplasmic actin enhances malignant features of tumor cells. The distinct participation of each cytoplasmic actin in the cell cycle driving was also observed. The goal of this study was to describe the diverse roles of cytoplasmic actins in the progression of chromosomal instability of MDA-MB-231 basal-like human carcinoma cell line. We performed traditional methods of chromosome visualization, as well as 3D-IF microscopy and western blotting for CENP-A detection/quantification, to investigate chromosome morphology. Downregulation of cytoplasmic actin isoforms alters the phenotype and karyotype of MDA-MB-231 breast cancer cells. Moreover, β-actin depletion leads to the progression of chromosomal instability with endoreduplication and aneuploidy increase. On the contrary, γ-actin downregulation results not only in reduced percentage of mitotic carcinoma cells, but leads to chromosome stability, reduced polyploidy, and aneuploidy.

scholarly journals CYTOGENETIC ANALYSIS OF CHROMOSOME 3 IN DROSOPHILA MELANOGASTER: THE HOMOEOTIC GENE COMPLEX IN POLYTENE CHROMOSOME INTERVAL 84A-B

Genetics ◽  
1980 ◽  
Vol 94 (1) ◽  
pp. 115-133 ◽  
Author(s):  
Thomas C Kaufman ◽  
Ricki Lewis ◽  
Barbara Wakimoto
Keyword(s):  
Drosophila Melanogaster ◽  
Polytene Chromosome ◽  
Cytogenetic Analysis ◽  
Proximal Portion ◽  
Chromosome 3 ◽  
Gene Complex ◽  
Anterior Portion ◽  
Cytogenetic Evidence ◽  
The Right

ABSTRACT Cytogenetic evidence is presented demonstrating that the 84A-B interval in the proximal portion of the right arm of chromosome 3 is the residence of a homoeotic gene complex similar to the bithorax locus. This complex, originally defined by the Antennapedia (A n t p) mutation, controls segmentation in the anterior portion of the organism. Different lesions within this complex homoeotically transform portions OI the prothorax, proboscis, antenna and eye and present clear analogies to similar lesions within the bithorax locus.

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