An international team of scientists studying a rare genetic disease discovered that a bundle of proteins with the long-established function of keeping chromosomes together also plays an important role in regulating genes in humans.
When gene regulation is disrupted in the multisystem genetic disease Cornelia deLange syndrome (CdLS), children may suffer missing hands or fingers, mental retardation, growth failure, cleft palate, heart defects, and other impairments. For families and patients, better knowledge of how those genes perturb normal development may enable researchers to design better diagnostic tests for the disease, and also provide targets for eventual treatments.
The study appeared today in the online journal Public Library of Science Biology (PloS Biology). The study leader was Ian D. Krantz, M.D., a specialist in pediatric genetics at The Children's Hospital of Philadelphia, where he directs a unique full-service clinic for children with CdLS.
First described in 1933, CdLS affects multiple organs and typically results in distinctive facial features, such as thin eyebrows that join, long eyelashes, thin lips, and excessive body hair. It affects an estimated one in 10,000 children. In the past, CdLS was only recognized in its very severe form that was often fatal in childhood; now most children with the condition live into adulthood. CdLS has a wide range of severity, with the mildest form manifesting as apparent isolated mental retardation and/or autism.
Krantz and colleagues investigated cohesin, a protein complex consisting of at least four proteins that form a ring that encircles chromosomes during cell division. Cohesin's long-established role, called "canonical" by the authors, is to control chromatids—the long strands that chromosomes form when they copy their DNA.
However, said Krantz, one open question is biology has been, "What does cohesin do when cells are not dividing?" His team's paper provides part of the answer, as the first study in human cells to identify genes that are dysregulated when cohesin doesn't work properly. Cohesin's role in dysregulation of gene expression (regulating the degree to which specific genes are turned on or off) has attracted considerable scientific interest with a recent discovery that it may also be implicated in cancer.
The current study builds on previous work by Krantz, who in 2004 co-led the study that discovered NIPBL, the first gene known to cause CdLS. Krantz partnered with his long-time collaborator, Laird S. Jackson, M.D., of Drexel University School of Medicine in Philadelphia. They discovered a second CdLS gene in 2007, and together they maintain the world's largest database of patients with CdLS.
In the current study, Krantz did a genome-wide analysis of mutant cell lines from 16 patients with severe CdLS. All the cells had mutations in the NIPBL gene, which plays a role in moving cohesin onto and off chromosomes.
The researchers used DNA microarrays, manufactured chips that measure how strongly different genes are expressed throughout a cell's full complement of DNA. The study team identified hundreds of genes that were dysregulated compared to controls, and also detected gene expression profiles that were unique to CdLS. Importantly, said Krantz, the expression levels of genes corresponded to the severity of the disease. The team replicated its findings in 101 additional samples.
"We found that gene expression is exquisitely regulated by cohesin and the NIBPL gene," said Krantz. "The gene expression patterns we found have great potential to be used in a diagnostic tool for Cornelia de Lange syndrome." He added that a gene array might also be developed as a single-platform tool to diagnose, from a patient's blood sample, not only CdLS, but also a variety of other developmental disorders.
Funding for the study came from the National Institute of Child Health and Development of the National Institutes of Health, the Pennsylvania Department of Health, the Genome Network Project and Grant-in-Aid for Scientific Research from the MEXT, a Japanese government ministry. First author Jinglan Liu receives a Cornelia de Lange Foundation Fellowship Grant.
Krantz's co-authors on the study came from Children's Hospital; the University of Pennsylvania School of Medicine; Drexel University School of Medicine; the Tokyo Institute of Technology; the Misakaenosono Mutsumi Developmental, Medical, and Welfare Center, in Isahaya, Japan; and the National University of Colombia, in Bogota, Colombia.
Liu et al, "Transcriptional dysregulation in NIPBL and cohesin mutant human cells," PloS Biology, published online, May 26, 2009.
About The Children's Hospital of Philadelphia: The Children's Hospital of Philadelphia was founded in 1855 as the nation's first pediatric hospital. Through its long-standing commitment to providing exceptional patient care, training new generations of pediatric healthcare professionals and pioneering major research initiatives, Children's Hospital has fostered many discoveries that have benefited children worldwide. Its pediatric research program is among the largest in the country, ranking second in National Institutes of Health funding. In addition, its unique family-centered care and public service programs have brought the 430-bed hospital recognition as a leading advocate for children and adolescents.
John Ascenzi | EurekAlert!
Further reports about: > CdLS > Cornelia de Lange syndrome > DNA > NIPBL > chromosomes > cleft palate > developmental disorder > diagnostic test > dysregulation of gene expression > excessive body hair > gene function > genetic disease > growth failure > heart defects > human cells > long eyelashes > mental retardation > specific gene > synthetic biology > thin eyebrows
The genes are not to blame
20.07.2018 | Technische Universität München
Targeting headaches and tumors with nano-submarines
20.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences