scholarly journals Rubisco Small Subunit, Chlorophyll a/b-Binding Protein and Sucrose:Fructan-6-Fructosyl Transferase Gene Expression and Sugar Status in Single Barley Leaf Cells in Situ. Cell Type Specificity and Induction by Light

2002 ◽  
Vol 130 (3) ◽  
pp. 1335-1348 ◽  
Author(s):  
C. Lu
1985 ◽  
Vol 5 (2) ◽  
pp. 419-421
Author(s):  
K M Zezulak ◽  
H Green

During the differentiation of preadipose 3T3 cells into adipose cells, the mRNAs for three proteins increase strikingly in abundance. To determine the degree of cell-type specificity in the expression of these mRNAs, we estimated their abundances in several nonadipose tissues of the mouse. None of these mRNAs was strictly confined to adipocytes, but the ensemble of three mRNAs was rather specific to adipocytes. Insofar as is revealed by these three markers, the distinctive phenotype of adipocytes is the result of the enhanced expression of a number of genes, none of which is completely silent in all other cell types.


eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Sinisa Hrvatin ◽  
Christopher P Tzeng ◽  
M Aurel Nagy ◽  
Hume Stroud ◽  
Charalampia Koutsioumpa ◽  
...  

Enhancers are the primary DNA regulatory elements that confer cell type specificity of gene expression. Recent studies characterizing individual enhancers have revealed their potential to direct heterologous gene expression in a highly cell-type-specific manner. However, it has not yet been possible to systematically identify and test the function of enhancers for each of the many cell types in an organism. We have developed PESCA, a scalable and generalizable method that leverages ATAC- and single-cell RNA-sequencing protocols, to characterize cell-type-specific enhancers that should enable genetic access and perturbation of gene function across mammalian cell types. Focusing on the highly heterogeneous mammalian cerebral cortex, we apply PESCA to find enhancers and generate viral reagents capable of accessing and manipulating a subset of somatostatin-expressing cortical interneurons with high specificity. This study demonstrates the utility of this platform for developing new cell-type-specific viral reagents, with significant implications for both basic and translational research.


2009 ◽  
Vol 83 (21) ◽  
pp. 10846-10856 ◽  
Author(s):  
Martyn K. White ◽  
Mahmut Safak ◽  
Kamel Khalili

ABSTRACT Polyomaviruses are a growing family of small DNA viruses with a narrow tropism for both the host species and the cell type in which they productively replicate. Species host range may be constrained by requirements for precise molecular interactions between the viral T antigen, host replication proteins, including DNA polymerase, and the viral origin of replication, which are required for viral DNA replication. Cell type specificity involves, at least in part, transcription factors that are necessary for viral gene expression and restricted in their tissue distribution. In the case of the human polyomaviruses, BK virus (BKV) replication occurs in the tubular epithelial cells of the kidney, causing nephropathy in kidney allograft recipients, while JC virus (JCV) replication occurs in the glial cells of the central nervous system, where it causes progressive multifocal leukoencephalopathy. Three new human polyomaviruses have recently been discovered: MCV was found in Merkel cell carcinoma samples, while Karolinska Institute Virus and Washington University Virus were isolated from the respiratory tract. We discuss control mechanisms for gene expression in primate polyomaviruses, including simian vacuolating virus 40, BKV, and JCV. These mechanisms include not only modulation of promoter activities by transcription factor binding but also enhancer rearrangements, restriction of DNA methylation, alternate early mRNA splicing, cis-acting elements in the late mRNA leader sequence, and the production of viral microRNA.


2021 ◽  
Author(s):  
Anthony Mark Raus ◽  
Tyson D Fuller ◽  
Nellie E Nelson ◽  
David A Valientes ◽  
Anita Bayat ◽  
...  

Aerobic exercise promotes physiological and molecular adaptations in neurons to influence brain function and behavior. The most well studied neurobiological consequences of exercise are those which underlie exercise-induced improvements in hippocampal memory, including the expression and regulation of the neurotrophic factor Bdnf. Whether aerobic exercise taking place during early-life periods of postnatal brain maturation has similar impacts on gene expression and its regulation remains to be investigated. Using unbiased next-generation sequencing we characterize gene expression programs and their regulation by specific, memory-associated histone modifications during juvenile-adolescent voluntary exercise (ELE). Traditional transcriptomic and epigenomic sequencing approaches have either used heterogeneous cell populations from whole tissue homogenates or flow cytometry for single cell isolation to distinguish cell types / subtypes. These methods fall short in providing cell-type specificity without compromising sequencing depth or procedure-induced changes to cellular phenotype. In this study, we use simultaneous isolation of translating mRNA and nuclear chromatin from a neuron-enriched cell population to more accurately pair ELE-induced changes in gene expression with epigenetic modifications. We employ a line of transgenic mice expressing the NuTRAP (Nuclear Tagging and Translating Ribosome Affinity Purification) cassette under the Emx1 promoter allowing for brain cell-type specificity. We then developed a technique that combines nuclear isolation using Isolation of Nuclei TAgged in Specific Cell Types (INTACT) with Translating Ribosomal Affinity Purification (TRAP) methods to determine cell type-specific epigenetic modifications influencing gene expression programs from a population of Emx1 expressing hippocampal neurons. Data from RNA-seq and CUT&RUN-seq were coupled to evaluate histone modifications influencing the expression of translating mRNA in neurons after early-life exercise (ELE). We also performed separate INTACT and TRAP isolations for validation of our protocol and demonstrate similar molecular functions and biological processes implicated by gene ontology (GO) analysis. Finally, as prior studies use tissue from opposite brain hemispheres to pair transcriptomic and epigenomic data from the same rodent, we take a bioinformatics approach to compare hemispheric differences in gene expression programs and histone modifications altered by by ELE. Our data reveal transcriptional and epigenetic signatures of ELE exposure and identify novel candidate gene-histone modification interactions for further investigation. Importantly, our novel approach of combined INTACT/TRAP methods from the same cell suspension allows for simultaneous transcriptomic and epigenomic sequencing in a cell-type specific manner.


2019 ◽  
Author(s):  
Demis A. Kia ◽  
David Zhang ◽  
Sebastian Guelfi ◽  
Claudia Manzoni ◽  
Leon Hubbard ◽  
...  

AbstractSubstantial genome-wide association study (GWAS) work in Parkinson’s disease (PD) has led to an increasing number of loci shown reliably and robustly to be associated with the increased risk of the disease. Prioritising causative genes and pathways from these studies has proven problematic. Here, we present a comprehensive analysis of PD GWAS data with expression and methylation quantitative trait loci (eQTL/mQTL) using Colocalisation analysis (Coloc) and transcriptome-wide association analysis (TWAS) to uncover putative gene expression and splicing mechanisms driving PD GWAS signals. Candidate genes were further characterised by determining cell-type specificity, weighted gene co-expression (WGNCA) and protein-protein interaction (PPI) networks.Gene-level analysis of expression revealed 5 genes (WDR6, CD38, GPNMB, RAB29, TMEM163) that replicated using both Coloc and TWAS analyses in both GTEx and Braineac expression datasets. A further 6 genes (ZRANB3, PCGF3, NEK1, NUPL2, GALC, CTSB) showed evidence of disease-associated splicing effects. Cell-type specificity analysis revealed that gene expression was overall more prevalent in glial cell-types compared to neurons. The WGNCA analysis showed that NUPL2 is a key gene in 3 modules implicated in catabolic processes related with protein ubiquitination (protein ubiquitination (p=7.47e-10) and ubiquitin-dependent protein catabolic process (p = 2.57e-17) in nucleus accumbens, caudate and putamen, while TMEM163 and ZRANB3 were both important in modules indicating regulation of signalling (p=1.33e-65] and cell communication (p=7.55e-35) in the frontal cortex and caudate respectively. PPI analysis and simulations using random networks demonstrated that the candidate genes interact significantly more with known Mendelian PD and parkinsonism proteins than would be expected by chance. The proteins core proteins this network were enriched for regulation of the ERBB receptor tyrosine protein kinase signalling pathways.Together, these results point to a number of candidate genes and pathways that are driving the associations observed in PD GWAS studies.


2019 ◽  
Author(s):  
Nestor Timonidis ◽  
Rembrandt Bakker ◽  
Paul Tiesinga

AbstractReconstructing brain connectivity at sufficient resolution for computational models designed to study the biophysical mechanisms underlying cognitive processes is extremely challenging. For such a purpose, a mesoconnectome that includes laminar and cell-type specificity would be a major step forward. We analysed the ability of gene expression patterns to predict cell-type and laminar specific projection patterns and analyzed the biological context of the most predictive groups of genes. To achieve our goal, we used publicly available volumetric gene expression and connectivity data and pre-processed it for prediction by averaging across brain regions, imputing missing values and rescaling. Afterwards, we predicted the strength of axonal projections and their binary form using expression patterns of individual genes and co-expression patterns of spatial gene modules.For predicting projection strength, we found that ridge (L2-regularized) regression had the highest cross-validated accuracy with a median r2 score of 0.54 which corresponded for binarized predictions to a median area under the ROC value of 0.89. Next, we identified 200 spatial gene modules using the dictionary learning and sparse coding approach. We found that these modules yielded predictions of comparable accuracy, with a median r2 score of 0.51. Finally, a gene ontology enrichment analysis of the most predictive gene groups resulted in significant annotations related to postsynaptic function.Taken together, we have demonstrated a prediction pipeline that can be used to perform multimodal data integration to improve the accuracy of the predicted mesoconnectome and support other neuroscience use cases.


1987 ◽  
Vol 7 (9) ◽  
pp. 3205-3211
Author(s):  
M Company ◽  
B Errede

Ty transposable element insertion mutations of Saccharomyces cerevisiae can cause cell-type-dependent activation of adjacent gene expression. Several cis-acting regulatory regions within Ty1 that are responsible for these effects were identified. A 211-base-pair (bp) region functions as an activator. This region includes the so-called U5 domain of delta and 145 bp of adjacent epsilon sequences. Unlike activation by the intact Ty1, activation by the 211-bp Ty1 subfragment is cell-type independent. The presence of a 112-bp fragment from a more distal region of Ty1 confers cell-type specificity to the activator. The 112-bp fragment includes sequences with homology to mammalian enhancers and to a yeast a/alpha control site. In addition, Ty1 regions that exert negative effects on gene expression were identified. These results demonstrate that the Ty1 transcriptional control region consists of multiple components with distinct regulatory functions.


1991 ◽  
Vol 39 (2) ◽  
pp. 171-176 ◽  
Author(s):  
K Porrello ◽  
S P Bhat ◽  
D Bok

Interphotoreceptor retinoid binding protein (IRBP) is a soluble glycolipoprotein located between the neurosensory retina and pigment epithelium, which may serve to transport vitamin A derivatives between these tissues. The specific cell type responsible for IRBP synthesis has not been well established. To address this issue, we have examined the expression of IRBP mRNA in human and cone-dominant ground squirrel retinas by in situ hybridization. Optimal labeling and histological resolution were achieved with 35S- and 3H-labeled anti-sense riboprobes made from a human IRBP cDNA clone, and semi-thin wax-embedded retinal sections. In human retina, label was localized over the inner segments of both rod and cone photoreceptors. Quantitative analysis demonstrated a fourfold higher density of label over rod inner segments. In ground squirrel retina, labeling was found almost exclusively over the inner segments of cones. The results indicate that in human retina both rods and cones express IRBP mRNA, albeit at different levels. In cone-dominant species such as the ground squirrel, cones are the principal cell type responsible for IRBP mRNA synthesis.


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