scholarly journals Cell-type-specific synthesis of murine immunoglobulin mu RNA from an adenovirus vector.

1986 ◽  
Vol 6 (1) ◽  
pp. 123-133 ◽  
Author(s):  
J E Ruether ◽  
A Maderious ◽  
D Lavery ◽  
J Logan ◽  
S M Fu ◽  
...  

The mouse immunoglobulin heavy-chain mu constant region gene was cloned into the early region 1B of an adenovirus type 5 vector to allow reproducible kinetics of expression of the mu gene in the presence of continuous host protein synthesis after infection by the recombinant. The immunoglobulin-adenovirus recombinant is helper independent in infecting human fibroblastic and B- and T-cell lines and expresses mu in a cell-type-specific manner. By Northern blot analysis, correctly polyadenylated and spliced E1B-mu S and E1B-mu m mRNAs are found to be equally abundant at steady state in fibroblasts. In contrast, and appropriately, only E1B-mu S mRNAs accumulate in a lambda light-chain-secreting myeloma cell line. Analysis of nascent transcripts pulse labeled in isolated nuclei demonstrates equimolar polymerase loading throughout the mu region in all cell types infected by mu-Ad. Thus, correct polyadenylation and splicing of E1B-mu S and E1B-mu m in fibroblasts does not require transcription termination in the region separating the mu S and mu m polyadenylation sites. Furthermore, differential expression of mu transcripts in the background of myeloma cells is regulated at the level of RNA processing and does not require the presence of the immunoglobulin heavy-chain enhancer or promoter element.

1986 ◽  
Vol 6 (1) ◽  
pp. 123-133
Author(s):  
J E Ruether ◽  
A Maderious ◽  
D Lavery ◽  
J Logan ◽  
S M Fu ◽  
...  

The mouse immunoglobulin heavy-chain mu constant region gene was cloned into the early region 1B of an adenovirus type 5 vector to allow reproducible kinetics of expression of the mu gene in the presence of continuous host protein synthesis after infection by the recombinant. The immunoglobulin-adenovirus recombinant is helper independent in infecting human fibroblastic and B- and T-cell lines and expresses mu in a cell-type-specific manner. By Northern blot analysis, correctly polyadenylated and spliced E1B-mu S and E1B-mu m mRNAs are found to be equally abundant at steady state in fibroblasts. In contrast, and appropriately, only E1B-mu S mRNAs accumulate in a lambda light-chain-secreting myeloma cell line. Analysis of nascent transcripts pulse labeled in isolated nuclei demonstrates equimolar polymerase loading throughout the mu region in all cell types infected by mu-Ad. Thus, correct polyadenylation and splicing of E1B-mu S and E1B-mu m in fibroblasts does not require transcription termination in the region separating the mu S and mu m polyadenylation sites. Furthermore, differential expression of mu transcripts in the background of myeloma cells is regulated at the level of RNA processing and does not require the presence of the immunoglobulin heavy-chain enhancer or promoter element.


1988 ◽  
Vol 8 (2) ◽  
pp. 988-992 ◽  
Author(s):  
J Weinberger ◽  
P S Jat ◽  
P A Sharp

The immunoglobulin heavy-chain enhancer is a cis-acting element which activates transcription of nearby genes only in cells of the lymphoid lineage. To identify the minimal sequences necessary to impart cell type transcriptional specificity, we tested the activity of several deletions and internal mutations in the mu enhancer. Experiments involving measurement of both chloramphenicol acetyltransferase activity and RNA levels indicated the presence of a dominant repressor element within the mu enhancer. This repressive activity was detected in fibroblasts but not in myeloma cells. Removal or disruption of this repressor element revealed the presence of elements within the mu enhancer that activate transcription in fibroblasts. Thus, enhancer tissue specificity is in part due to the composite of both constitutive activation and cell-type-specific repressive activity. The possible biological roles of this phenomenon are discussed.


1988 ◽  
Vol 8 (2) ◽  
pp. 988-992
Author(s):  
J Weinberger ◽  
P S Jat ◽  
P A Sharp

The immunoglobulin heavy-chain enhancer is a cis-acting element which activates transcription of nearby genes only in cells of the lymphoid lineage. To identify the minimal sequences necessary to impart cell type transcriptional specificity, we tested the activity of several deletions and internal mutations in the mu enhancer. Experiments involving measurement of both chloramphenicol acetyltransferase activity and RNA levels indicated the presence of a dominant repressor element within the mu enhancer. This repressive activity was detected in fibroblasts but not in myeloma cells. Removal or disruption of this repressor element revealed the presence of elements within the mu enhancer that activate transcription in fibroblasts. Thus, enhancer tissue specificity is in part due to the composite of both constitutive activation and cell-type-specific repressive activity. The possible biological roles of this phenomenon are discussed.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Houri Hintiryan ◽  
Ian Bowman ◽  
David L. Johnson ◽  
Laura Korobkova ◽  
Muye Zhu ◽  
...  

AbstractThe basolateral amygdalar complex (BLA) is implicated in behaviors ranging from fear acquisition to addiction. Optogenetic methods have enabled the association of circuit-specific functions to uniquely connected BLA cell types. Thus, a systematic and detailed connectivity profile of BLA projection neurons to inform granular, cell type-specific interrogations is warranted. Here, we apply machine-learning based computational and informatics analysis techniques to the results of circuit-tracing experiments to create a foundational, comprehensive BLA connectivity map. The analyses identify three distinct domains within the anterior BLA (BLAa) that house target-specific projection neurons with distinguishable morphological features. We identify brain-wide targets of projection neurons in the three BLAa domains, as well as in the posterior BLA, ventral BLA, posterior basomedial, and lateral amygdalar nuclei. Inputs to each nucleus also are identified via retrograde tracing. The data suggests that connectionally unique, domain-specific BLAa neurons are associated with distinct behavior networks.


Author(s):  
Hee-Dae Kim ◽  
Jing Wei ◽  
Tanessa Call ◽  
Nicole Teru Quintus ◽  
Alexander J. Summers ◽  
...  

AbstractDepression is the leading cause of disability and produces enormous health and economic burdens. Current treatment approaches for depression are largely ineffective and leave more than 50% of patients symptomatic, mainly because of non-selective and broad action of antidepressants. Thus, there is an urgent need to design and develop novel therapeutics to treat depression. Given the heterogeneity and complexity of the brain, identification of molecular mechanisms within specific cell-types responsible for producing depression-like behaviors will advance development of therapies. In the reward circuitry, the nucleus accumbens (NAc) is a key brain region of depression pathophysiology, possibly based on differential activity of D1- or D2- medium spiny neurons (MSNs). Here we report a circuit- and cell-type specific molecular target for depression, Shisa6, recently defined as an AMPAR component, which is increased only in D1-MSNs in the NAc of susceptible mice. Using the Ribotag approach, we dissected the transcriptional profile of D1- and D2-MSNs by RNA sequencing following a mouse model of depression, chronic social defeat stress (CSDS). Bioinformatic analyses identified cell-type specific genes that may contribute to the pathogenesis of depression, including Shisa6. We found selective optogenetic activation of the ventral tegmental area (VTA) to NAc circuit increases Shisa6 expression in D1-MSNs. Shisa6 is specifically located in excitatory synapses of D1-MSNs and increases excitability of neurons, which promotes anxiety- and depression-like behaviors in mice. Cell-type and circuit-specific action of Shisa6, which directly modulates excitatory synapses that convey aversive information, identifies the protein as a potential rapid-antidepressant target for aberrant circuit function in depression.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
John A. Halsall ◽  
Simon Andrews ◽  
Felix Krueger ◽  
Charlotte E. Rutledge ◽  
Gabriella Ficz ◽  
...  

AbstractChromatin configuration influences gene expression in eukaryotes at multiple levels, from individual nucleosomes to chromatin domains several Mb long. Post-translational modifications (PTM) of core histones seem to be involved in chromatin structural transitions, but how remains unclear. To explore this, we used ChIP-seq and two cell types, HeLa and lymphoblastoid (LCL), to define how changes in chromatin packaging through the cell cycle influence the distributions of three transcription-associated histone modifications, H3K9ac, H3K4me3 and H3K27me3. We show that chromosome regions (bands) of 10–50 Mb, detectable by immunofluorescence microscopy of metaphase (M) chromosomes, are also present in G1 and G2. They comprise 1–5 Mb sub-bands that differ between HeLa and LCL but remain consistent through the cell cycle. The same sub-bands are defined by H3K9ac and H3K4me3, while H3K27me3 spreads more widely. We found little change between cell cycle phases, whether compared by 5 Kb rolling windows or when analysis was restricted to functional elements such as transcription start sites and topologically associating domains. Only a small number of genes showed cell-cycle related changes: at genes encoding proteins involved in mitosis, H3K9 became highly acetylated in G2M, possibly because of ongoing transcription. In conclusion, modified histone isoforms H3K9ac, H3K4me3 and H3K27me3 exhibit a characteristic genomic distribution at resolutions of 1 Mb and below that differs between HeLa and lymphoblastoid cells but remains remarkably consistent through the cell cycle. We suggest that this cell-type-specific chromosomal bar-code is part of a homeostatic mechanism by which cells retain their characteristic gene expression patterns, and hence their identity, through multiple mitoses.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jinting Guan ◽  
Yiping Lin ◽  
Yang Wang ◽  
Junchao Gao ◽  
Guoli Ji

Abstract Background Genome-wide association studies have identified genetic variants associated with the risk of brain-related diseases, such as neurological and psychiatric disorders, while the causal variants and the specific vulnerable cell types are often needed to be studied. Many disease-associated genes are expressed in multiple cell types of human brains, while the pathologic variants affect primarily specific cell types. We hypothesize a model in which what determines the manifestation of a disease in a cell type is the presence of disease module comprised of disease-associated genes, instead of individual genes. Therefore, it is essential to identify the presence/absence of disease gene modules in cells. Methods To characterize the cell type-specificity of brain-related diseases, we construct human brain cell type-specific gene interaction networks integrating human brain nucleus gene expression data with a referenced tissue-specific gene interaction network. Then from the cell type-specific gene interaction networks, we identify significant cell type-specific disease gene modules by performing statistical tests. Results Between neurons and glia cells, the constructed cell type-specific gene networks and their gene functions are distinct. Then we identify cell type-specific disease gene modules associated with autism spectrum disorder and find that different gene modules are formed and distinct gene functions may be dysregulated in different cells. We also study the similarity and dissimilarity in cell type-specific disease gene modules among autism spectrum disorder, schizophrenia and bipolar disorder. The functions of neurons-specific disease gene modules are associated with synapse for all three diseases, while those in glia cells are different. To facilitate the use of our method, we develop an R package, CtsDGM, for the identification of cell type-specific disease gene modules. Conclusions The results support our hypothesis that a disease manifests itself in a cell type through forming a statistically significant disease gene module. The identification of cell type-specific disease gene modules can promote the development of more targeted biomarkers and treatments for the disease. Our method can be applied for depicting the cell type heterogeneity of a given disease, and also for studying the similarity and dissimilarity between different disorders, providing new insights into the molecular mechanisms underlying the pathogenesis and progression of diseases.


1989 ◽  
Vol 92 (2) ◽  
pp. 231-239
Author(s):  
P.I. Francz ◽  
K. Bayreuther ◽  
H.P. Rodemann

Methods for the selective enrichment of various subpopulations of the human skin fibroblast cell line HH-8 have been developed. These methods permit the selection of homogeneous populations of the three mitotic fibroblast cell types MF I, II and III, and the four postmitotic cell types PMF IV, V, VI and VII. These seven cell types exhibit differentiation-dependent and cell-type-specific patterns of [35S]methionine-labelled polypeptides in total soluble cytoplasmic and nuclear proteins, also in membrane-bound proteins, and in secreted proteins. In the differentiation sequence MF II-MF III-PMF IV - PMF V - PMF VI 14 cell-type-specific marker proteins have been found in the cytoplasmic and nuclear fraction, also 24 cell-type-specific marker proteins have been found in the membrane-bound protein fraction, and 11 cell-type-specific marker proteins in the secreted protein fraction. Markers in spontaneously arising and experimentally selected or induced populations of a single fibroblast cell type were found to be identical.


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