ChIA-PET: Novel Method For 3-D Whole Genome Mapping Research Nov 9, 2009
The technology is ChIA-PET (Chromatin Interaction Analysis using Paired End Tag sequencing). Chromatin is a complex combination of DNA and proteins that make up chromosomes ... "In thinking about how this can happen, many scientists hypothesized that chromatin interactions -- 3-dimensional loops in DNA -- might be what allow these regions to remotely talk to genes," Dr. Fullwood added. (Science Daily)
Silence Of The Genes: Researchers Get First Look At Gene-Silencing Human RISC-Loading Complex Oct 15, 2009
This process is used in a number of important activities, including viral defense, chromatin remodeling, genome rearrangement, developmental timing, brain morphogenesis and stem cell maintenance. Doudna, Nogales and their colleagues have identified the central component of the RISC-loading complex as the Dicer enzyme and that the human version is L-shaped. (Science Daily)
Mechanism of retinoic acid-driven myogenesis Oct 8, 2009
By chromatin immunoprecipitation, RA receptors (RARs) bound directly to regulatory regions in the Wnt3a, Pax3, and Meox1 genes and RA activated a beta-catenin-responsive promoter in aggregated P19 cells. In the presence of a dominant negative beta-catenin/engrailed repressor fusion protein, RA could not bypass the inhibition of skeletal myogenesis nor upregulate Meox1 or MyoD. Thus, RA functions both upstream and downstream of Wnt signalling. (BioMed Central)
Researchers Determine Composition Of Centromeric Chromatin Oct 5, 2009
"These data support a new model for the structure of centromeric nucleosomes and reinforce the importance of both structure and function of octameric nucleosomes in the epigenetic propagation of centromeric chromatin," said Raymond Camahort, Ph ... "Many lines of evidence indicate that centromeric chromatin is evolutionarily conserved from yeast to man," said Jennifer Gerton, Ph ... 20, 2009) Scientists have found that a class of chromatin proteins is crucial for maintaining the structure and... (Science Daily)
What is Gender Testing and is it Ri... Sep 11, 2009
The Sydney Daily Telegraph reports that Semenya has no ovaries and adds she has internal testes - the male sexual organs which produce testosterone (and) three times the amount of testosterone that a normal female would have" (2009). According to broadcast , the International Amateur Athletics Federation (IAAF) is considering stripping 18 year-old Semenya of her Olympic medal. But if these reports are accurate, how did officials determine that Semenya is a hermaphrodite? What is Gender Testing?... (Suite101.com)
'Swiss Army Knife' Protein Plays Unexpected Role Protecting Chromosome Tips; Possible Tie To Metastatic Cancer Aug 17, 2009
Chromosomes are made of DNA that is tightly intertwined with proteins called histones to form chromatin. Chromatin is a condensed structure that forms a natural barrier inhibiting access to DNA. Gcn5 was previously known for its role in a complex of proteins that loosens chromatin to allow access to DNA by the cell's DNA repair machinery and by transcription factors that launch the process of gene expression. (Science Daily)
Conaway Lab uncovers function of potential cancer-causing gene product Aug 8, 2009
"We've been able to demonstrate that the protein encoded by the Alc1 gene is, in fact, a chromatin remodeling enzyme," explained Aaron Gottschalk, lead author on the paper and a University of Kansas Medical Center graduate student conducting research in the Conaway Lab ... "Finding that Parp1 and poly(ADP-ribose) recruit the chromatin remodeling enzyme Alc1 to chromatin and activate Alc1 activity suggests a mechanism by which they might function.". (EurekAlert!)
Remodeling of the chromatin structure of the facioscapulohumeral muscular dystrophy (FSHD) locus and upregulation of FSHD-related gene 1 (FRG1) expression during human myogenic differentiation Jul 16, 2009
A number of candidate FSHD genes, adenine nucleotide translocator 1 gene (ANT1), FSHD-related gene 1 (FRG1), FRG2 and DUX4c, upstream of the D4Z4 array (FSHD locus), and double homeobox chromosome 4 (DUX4) within the repeat itself, are upregulated in some patients, thus suggesting an underlying perturbation of the chromatin structure ... In the context of myogenic differentiation, we compared the chromatin structure and tridimensional interaction of the D4Z4 array and FRG1 gene promoter, and... (BioMed Central)
LincRNAs serve as genetic air-traffic controllers Jul 15, 2009
"It has long been a mystery as to how widely expressed proteins shape the fate of cells. How does the same protein know to regulate one genomic location in a brain cell and regulate a different genomic region in a liver cell? Our study suggests that in the same way that air traffic controllers organize planes in the air, lincRNAs may be organizing key chromatin complexes in the cell.". Inspired by a lincRNA called HOTAIR -- which is known to bind key chromatin modifier proteins and to assist in... (EurekAlert!)
Stem Cells' 'Suspended' State Preserved By Key Step, Scientists Report Jul 11, 2009
This step, known as chromatin remodeling, allows the cell's protein-making machinery to gain access to the DNA and transform progenitor cells into specialized cells and tissue, such as neurons, muscle and bone. A number of genes are known to trigger chromatin remodeling, allowing small sections of DNA to become accessible in order to make specific proteins ... The team plans to study chromatin remodeling in still more detail to clarify what other molecules work in concert with the Chd1 gene to... (Science Daily)
Vitamin A Derivative Provides Clues To Better Breast Cancer Drugs Jul 7, 2009
So the team combined two laboratory techniques--a process known as "ChIP-chip analysis" that blends chromatin immunoprecipitation (ChIP), to see where the retinoic acid receptors bound to the genome, with micro-array gene-chip analysis, to measure expression levels of specific genes. The combination enabled them to map out all the genetic effects of retinoic acid and its receptors in a cell line derived from patients with breast cancers that were fueled by estrogen. (Science Daily)
BRIT1 allows DNA repair teams access to damaged sites Jun 20, 2009
Chromosomes are made of DNA that is tightly intertwined with proteins called histones to form chromatin. Chromatin is a very condensed structure that forms a natural barrier inhibiting access to genes, said first author Guang Peng, Ph ... ATP-dependent chromatin remodeling is a fundamental mechanism used by cells to relax chromatin in DNA repair, but the detailed molecular mechanism by which it is recruited to DNA lesions in response to damage signaling has been largely unknown. (EurekAlert!)
Normal Development Of Cells With Abnormal Numbers Of Nuclei Jun 18, 2009
20, 2009) Scientists have found that a class of chromatin proteins is crucial for maintaining the structure and function of chromosomes and the normal development of eukaryotic. (Jan. (Science Daily)
Two Signals -- From Within And Out Of Cell -- Specify Motor Neuron Differentiation Jun 16, 2009
ScienceDaily (June 15, 2009) Two signals an external one from retinoic acid and an internal one from the transcription factor Neurogenin2 cooperate to activate chromatin (the basic material of chromosomes) and help determine that certain nerve progenitor cells become motor neurons, said researchers from Baylor College of Medicine in a report in the current issue of the journal Neuron ... This causes a chemical reaction called acetylation of the histones (the spools around which DNA winds in the... (Science Daily)
Cocaine-linked Genes Enhance Behavioral Effects Of Addiction May 16, 2009
Dr. Nestler and colleagues combined sophisticated and highly sensitive genetic isolation and screening techniques to study regulation of gene transcription in the mouse NAc, including regulation of chromatin structure, after repeated administration of cocaine. The results of this novel analysis significantly refined the understanding of cocaine-regulated gene transcription in general, and advanced knowledge of the specific role of two transcription factors known to play a prominent role in... (Science Daily)
Even In Our Genome, Good Fences Make Good Neighbors May 16, 2009
To fit such a long molecule inside a cell's nucleus and keep everything neatly organized, the DNA is threaded around histone proteins and coiled up in a highly condensed structure called heterochromatin. In areas of gene activity, the tightly packed chromatin is unfurled just enough to make the DNA accessible to regulatory proteins ... In many different types of cancers, however, including breast, lung, liver, and pancreatic tumors, as well as multiple myeloma and lymphoma, the tumor suppressor... (Science Daily)
Alzheimer's Reversal One Step Closer? May 7, 2009
"This will help elucidate the mechanisms by which chromatin remodeling regulates memory," she said ... Proteins called histones act as spools around which DNA winds, forming a structure in the cell nucleus known as chromatin ... Histones are modified in various ways, including through a process called acetylation, which in turn modifies chromatin shape and structure. (Science Daily)
Stem Cells For The Damaged Heart: Key Factors In Heart Cell Creation Identified May 3, 2009
"Our previous studies had shown that chromatin remodeling complexes were important," said Dr. Bruneau ... When all three are introduced, Baf60c helps open up the closed chromatin, and lets Tbx5 and Gata4 work together to turn on the heart genes. (Science Daily)
Cancer Mutations In The Heart Of Gene Regulation Apr 7, 2009
The composite DNA protein structure, called chromatin, is not simply a scaffold, but plays an active role in controlling gene activity. The UTX protein alters a key organising subunit component of chromatin, called a histone ... Chromatin, the most-studied DNA protein structure, consists largely of DNA in association with five classes of proteins called histones. (Science Daily)
What's Driving Specific Patterns Of Gene Expression Among Cell Types? Mar 28, 2009
"In our analyses, we were surprised to find that the chromatin signatures at promoter sites were similar across all cells. However, we found that enhancers are marked with highly cell-type specific modification patterns. These patterns suggested that enhancers are of primary importance in the differentiation of specific cell types.". Using previously described chromatin signatures for enhancers, the scientists mapped 55,000 elements that differentiate gene expression in cervical cancer, leukemia... (Science Daily)
Protein Complex Shown To Play Pivotal Role In Stem Cell Development Mar 11, 2009
Like a musician tuning an instrument, the complex associates with and adjusts the expression levels of other proteins important in pluripotency, perhaps by affecting how the DNA is packaged within the cells in strands called chromatin ... "We've identified a specific mechanism to maintain pluripotency that involves large-scale, genome-wide chromatin remodeling," said Gerald Crabtree, MD. "The results are rather spectacular. They show clearly that the complex binds to and works in near-perfect... (Science Daily)
Roles Of DNA Packaging Protein Revealed Feb 21, 2009
20, 2009) Scientists at Albert Einstein College of Medicine of Yeshiva University have found that a class of chromatin proteins is crucial for maintaining the structure and function of chromosomes and the normal development of eukaryotic organisms ... A chromosome's combination of histone proteins and DNA is referred to as chromatin ... The researchers found that H1 is necessary for holding together pericentric heterochromatin, the chromatin region close to the center of each chromosome. (Science Daily)
Roles of DNA packaging protein revealed by Einstein scientists Feb 13, 2009
February 12, 2009 - (BRONX, NY) - Scientists at Albert Einstein College of Medicine of Yeshiva University have found that a class of chromatin proteins is crucial for maintaining the structure and function of chromosomes and the normal development of eukaryotic organisms ... A chromosome's combination of histone proteins and DNA is referred to as chromatin ... The researchers found that H1 is necessary for holding together pericentric heterochromatin, the chromatin region close to the center of... (EurekAlert!)
Next gen sequencing technology pinpoint 'on-off switches' in genomes Feb 13, 2009
Using what's called ChIP-Sequencing or ChIP-Seq, chromatin immunoprecipitation (ChIP) is combined with massively parallel DNA sequencing to identify binding sites of DNA-associated proteins. Traditionally researchers have relied on evolution to guide them to non-coding sequences that are likely to have a functionsuch as enhancing the expression of genes. (EurekAlert!)
Scientists ID Enzyme Causing Brain Cell Death Feb 7, 2009
The scientists focused on an enzyme called HDAC1, which configures chromatin, the structural component of chromosomes. Tests in mice found that when HDAC1 is blocked, some neurons start to replicate their DNA as if they were about to divide. (MEDLINEplus)
