Chromatin Structure and Gene Expression in Germ Line and Somatic Cells

1986 ◽  
pp. 205-243
Author(s):  
Mark Groudine ◽  
Maxine Linial
Keyword(s):  
Gene Expression ◽  
Chromatin Structure ◽  
Germ Line ◽  
Somatic Cells

scholarly journals Hypothesis of the conjunct expression gene: can random mutation explain the phenotypic variability?

2018 ◽  
Author(s):  
Víctor A Zapata Trejo
Keyword(s):  
Gene Expression ◽  
Germ Line ◽  
Phenotypic Variability ◽  
Somatic Cells ◽  
Random Mutation ◽  
Differentiated Cells ◽  
Undifferentiated Cells

The epigenome regulates the gene expression of all differentiated cells and indicates which specific genes must be transcribed. It is argued that the expression factors that act in specific genes of the somatic cells involved in a behavior also act in the partial transcription of the same genes in the most undifferentiated cells of the germ line. It is proposed how a probabilistic view of the random mutation can explain the evolution of the phenotypes and integrate all the evidence pointing to a conjunct evolution with the environment.

scholarly journals Can random mutation explain the phenotypic variability?

2018 ◽  
Author(s):  
Víctor A Zapata Trejo
Keyword(s):  
Gene Expression ◽  
Germ Line ◽  
Phenotypic Variability ◽  
Somatic Cells ◽  
Random Mutation ◽  
Differentiated Cells ◽  
Undifferentiated Cells

The epigenome regulates the gene expression of all differentiated cells and indicates which specific genes must be transcribed. It is argued that the expression factors that act in specific genes of the somatic cells involved in a behavior also act in the partial transcription of the same genes in the most undifferentiated cells of the germ line. It is proposed how a probabilistic view of the random mutation can explain the evolution of the phenotypes and integrate all the evidence pointing to a conjunct evolution with the environment.

scholarly journals Mapping chromatin accessibility and active regulatory elements reveals pathological mechanisms in human gliomas

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Karolina Stępniak ◽  
Magdalena A. Machnicka ◽  
Jakub Mieczkowski ◽  
Anna Macioszek ◽  
Bartosz Wojtaś ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chromatin Structure ◽  
Molecular Mechanisms ◽  
Genome Mapping ◽  
Malignant Gliomas ◽  
Regulatory Elements ◽  
Chromatin Accessibility ◽  
Multiple Tumor ◽  
Genes Encoding ◽  
Methylation Patterns

AbstractChromatin structure and accessibility, and combinatorial binding of transcription factors to regulatory elements in genomic DNA control transcription. Genetic variations in genes encoding histones, epigenetics-related enzymes or modifiers affect chromatin structure/dynamics and result in alterations in gene expression contributing to cancer development or progression. Gliomas are brain tumors frequently associated with epigenetics-related gene deregulation. We perform whole-genome mapping of chromatin accessibility, histone modifications, DNA methylation patterns and transcriptome analysis simultaneously in multiple tumor samples to unravel epigenetic dysfunctions driving gliomagenesis. Based on the results of the integrative analysis of the acquired profiles, we create an atlas of active enhancers and promoters in benign and malignant gliomas. We explore these elements and intersect with Hi-C data to uncover molecular mechanisms instructing gene expression in gliomas.

scholarly journals Relation of Gene Expression Phenotype to Immunoglobulin Mutation Genotype in B Cell Chronic Lymphocytic Leukemia

2001 ◽  
Vol 194 (11) ◽  
pp. 1639-1648 ◽  
Author(s):  
Andreas Rosenwald ◽  
Ash A. Alizadeh ◽  
George Widhopf ◽  
Richard Simon ◽  
R. Eric Davis ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Germ Line ◽  
Gene Expression Signature ◽  
Lymphocytic Leukemia ◽  
Common Mechanism ◽  
Human Leukemia ◽  
Mutational Status ◽  
Cell Chronic Lymphocytic Leukemia

The most common human leukemia is B cell chronic lymphocytic leukemia (CLL), a malignancy of mature B cells with a characteristic clinical presentation but a variable clinical course. The rearranged immunoglobulin (Ig) genes of CLL cells may be either germ-line in sequence or somatically mutated. Lack of Ig mutations defined a distinctly worse prognostic group of CLL patients raising the possibility that CLL comprises two distinct diseases. Using genomic-scale gene expression profiling, we show that CLL is characterized by a common gene expression “signature,” irrespective of Ig mutational status, suggesting that CLL cases share a common mechanism of transformation and/or cell of origin. Nonetheless, the expression of hundreds of other genes correlated with the Ig mutational status, including many genes that are modulated in expression during mitogenic B cell receptor signaling. These genes were used to build a CLL subtype predictor that may help in the clinical classification of patients with this disease.

The ethics of genome editing in the clinic: A dose of realism for healthcare leaders

2017 ◽  
Vol 30 (3) ◽  
pp. 159-163
Author(s):  
Tania Bubela ◽  
Yael Mansour ◽  
Dianne Nicol
Keyword(s):  
Genome Editing ◽  
Germ Line ◽  
Genetic Diseases ◽  
Somatic Cells ◽  
Clinical Translation ◽  
Preclinical Research ◽  
Societal Issues ◽  
Realistic Assessment ◽  
Healthcare Leaders

Genome editing technologies promise therapeutic advances for genetic diseases. We discuss the ethical and societal issues raised by these technologies, including their use in preclinical research, their potential to address mutations in somatic cells, and their potential to make germ line alterations that may be passed to subsequent generations. We call for a proportionate response from health leaders based on a realistic assessment of benefits, risks, and timelines for clinical translation.

Insertion and excision of Caenorhabditis elegans transposable element Tc1

1988 ◽  
Vol 8 (2) ◽  
pp. 737-746
Author(s):  
D Eide ◽  
P Anderson
Keyword(s):  
Amino Acid ◽  
Caenorhabditis Elegans ◽  
Transposable Element ◽  
Dna Sequences ◽  
Germ Line ◽  
Consensus Sequence ◽  
Somatic Cells ◽  
Chain Gene ◽  
Imprecise Excision ◽  
Insertion Sites

The transposable element Tc1 is responsible for most spontaneous mutations that occur in Caenorhabditis elegans variety Bergerac. We investigated the genetic and molecular properties of Tc1 transposition and excision. We show that Tc1 insertion into the unc-54 myosin heavy-chain gene was strongly site specific. The DNA sequences of independent Tc1 insertion sites were similar to each other, and we present a consensus sequence for Tc1 insertion that describes these similarities. We show that Tc1 excision was usually imprecise. Tc1 excision was imprecise in both germ line and somatic cells. Imprecise excision generated novel unc-54 alleles that had amino acid substitutions, amino acid insertions, and, in certain cases, probably altered mRNA splicing. The DNA sequences remaining after Tc1 somatic excision were the same as those remaining after germ line excision, but the frequency of somatic excision was at least 1,000-fold higher than that of germ line excision. The genetic properties of Tc1 excision, combined with the DNA sequences of the resulting unc-54 alleles, demonstrated that excision was dependent on Tc1 transposition functions in both germ line and somatic cells. Somatic excision was not regulated in the same strain-specific manner as germ-line excision was. In a genetic background where Tc1 transposition and excision in the germ line was not detectable, Tc1 excision in the soma still occurred at high frequency.

Retrovirus-induced interference with collagen I gene expression in Mov13 fibroblasts is maintained in the absence of DNA methylation

1991 ◽  
Vol 11 (1) ◽  
pp. 47-54
Author(s):  
H Chan ◽  
S Hartung ◽  
M Breindl
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Chromatin Structure ◽  
Transcriptional Activity ◽  
Xenopus Laevis Oocytes ◽  
Regulatory Sequences ◽  
Type I ◽  
Wild Type ◽  
Col1a1 Gene

We have studied the role of DNA methylation in repression of the murine alpha 1 type I collagen (COL1A1) gene in Mov13 fibroblasts. In Mov13 mice, a retroviral provirus has inserted into the first intron of the COL1A1 gene and blocks its expression at the level of transcriptional initiation. We found that regulatory sequences in the COL1A1 promoter region that are involved in the tissue-specific regulation of the gene are unmethylated in collagen-expressing wild-type fibroblasts and methylated in Mov13 fibroblasts, confirming and extending earlier observations. To directly assess the role of DNA methylation in the repression of COL1A1 gene transcription, we treated Mov13 fibroblasts with the demethylating agent 5-azacytidine. This treatment resulted in a demethylation of the COL1A1 regulatory sequences but failed to activate transcription of the COL1A1 gene. Moreover, the 5-azacytidine treatment induced a transcription-competent chromatin structure in the retroviral sequences but not in the COL1A1 promoter. In DNA transfection and microinjection experiments, we found that the provirus interfered with transcriptional activity of the COL1A1 promoter in Mov13 fibroblasts but not in Xenopus laevis oocytes. In contrast, the wild-type COL1A1 promoter was transcriptionally active in Mov13 fibroblasts. These experiments showed that the COL1A1 promoter is potentially transcriptionally active in the presence of proviral sequences and that Mov13 fibroblasts contain the trans-acting factors required for efficient COL1A1 gene expression. Our results indicate that the provirus insertion in Mov13 can inactivate COL1A1 gene expression at several levels. It prevents the developmentally regulated establishment of a transcription-competent methylation pattern and chromatin structure of the COL1A1 domain and, in the absence of DNA methylation, appears to suppress the COL1A1 promoter in a cell-specific manner, presumably by assuming a dominant chromatin structure that may be incompatible with transcriptional activity of flanking cellular sequences.

scholarly journals KH-type splicing regulatory protein is a new component of chromatoid body

Reproduction ◽  
2017 ◽  
Vol 154 (6) ◽  
pp. 723-733 ◽  
Author(s):  
Huijuan Zhang ◽  
Guishuan Wang ◽  
Lin Liu ◽  
Xiaolin Liang ◽  
Yu Lin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Germ Cell ◽  
Knockout Mice ◽  
Binding Protein ◽  
Regulatory Protein ◽  
Somatic Cells ◽  
Chromatoid Body ◽  
Mechanistic Insight ◽  
Insight Into

The chromatoid body (CB) is a specific cloud-like structure in the cytoplasm of haploid spermatids. Recent findings indicate that CB is identified as a male germ cell-specific RNA storage and processing center, but its function has remained elusive for decades. In somatic cells, KH-type splicing regulatory protein (KSRP) is involved in regulating gene expression and maturation of select microRNAs (miRNAs). However, the function of KSRP in spermatogenesis remains unclear. In this study, we showed that KSRP partly localizes in CB, as a component of CB. KSRP interacts with proteins (mouse VASA homolog (MVH), polyadenylate-binding protein 1 (PABP1) and polyadenylate-binding protein 2 (PABP2)), mRNAs (Tnp2 and Odf1) and microRNAs (microRNA-182) in mouse CB. Moreover, KSRP may regulate the integrity of CB via DDX5-miRNA-182 pathway. In addition, we found abnormal expressions of CB component in testes of Ksrp-knockout mice and of patients with hypospermatogenesis. Thus, our results provide mechanistic insight into the role of KSRP in spermatogenesis.

scholarly journals Can random mutation explain phenotypic variability?

2018 ◽  
Author(s):  
Víctor Alejandro Zapata Trejo
Keyword(s):  
Gene Expression ◽  
Somatic Cell ◽  
Germ Line ◽  
Phenotypic Variability ◽  
Random Mutation ◽  
Differentiated Cells ◽  
Undifferentiated Cells ◽  
Joint Evolution

The epigenome regulates the gene expression of all differentiated cells and indicates which specific genes must be transcribed. It is argued that the expression factors that act on specific genes of the somatic cell involved in a behavior also act on the transcription of the same genes in the most undifferentiated cells of the germ line. It is proposed how a probabilistic view of the random mutation can explain the evolution of the phenotypes and integrate all the evidence pointing to a joint evolution with the environment.

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