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Nine New X-Chromosome Genes Associated with Learning Disabilities

Researchers have identified nine new genes on the X-chromosome that, when mutated, are associated with learning disabilities. "We sequenced 720 out of the approximately 800 known genes on the X chromosome in more than 200 families affected by X-linked learning disabilities," explained Professor Michael Stratton, from the Wellcome Trust Sanger Institute. "This is the largest sequencing study of complex disease ever reported." Learning disability is significantly more common in males than in females, and genetic causes have long been sought on the X-chromosome as males have only one X chromosome and so a gene mutation on the X is more likely to have an effect in males than in females. These new findings are expected to aid the diagnoses of X-linked learning disabilities and to enable more comprehensive genetic counseling. [Press release] [Nature Genetics abstract]

Synthesis of Anti-Leukemia Compounds from South Pacific Sponge

Scientists at the Scripps Research Institute have succeeded in synthesizing kapakahines, compounds with anti-leukemia potential that are normally produced in vanishingly small quantities by the South Pacific tube-type sponge Cripbrochalina olemda. With the synthetic process in hand, it will be possible, for the first time, to produce kapakahines in quantities sufficient for thorough study of their effectiveness in combating leukemia. [Press release] [JACS abstract]

Origins of Deadly Prostate Cancer Traced to Single Aberrant Cell

The origins of metastatic prostate cancer cells can be traced to a single original cancer cell in individuals. This is the conclusion of a 14-year autopsy-based study of copy number variation in the cells of prostate cancer victims. The study was carried out by researchers at Johns Hopkins and collaborating institutions. The findings call into question current views of the origins of primary prostate cancer and suggest that the genomic profile of prostate cancer metastases should inform therapeutic decisions. [Press release] [Nature Medicine abstract]

Possible Cell Adhesion Role for Normal Prion Protein

Scientist have reported the creation of a strong loss-of-function phenotype for the normal prion protein (PrP) in zebrafish embryos. This phenotype is characterized by the loss of embryonic cell adhesion and arrested gastrulation. The results of additional experiments indicate that the normal prion protein (1) mediates Ca+2-independent homophilic cell adhesion and signaling; and (2) modulates Ca+2-dependent cell adhesion by regulating the delivery of E-cadherin to the plasma membrane. The authors stated that their data uncover evolutionarily conserved roles of PrP in cell communication, which ultimately impinge on the stability of adherens cell junctions during embryonic development. The results were published in PLoS Biology, and an accompanying paper comments on the results.

Inbreeding Role in Extinction of the Spanish Habsburg Dynasty

Statistical genetic evidence supports the history-based theory that inbreeding may have played a role in the extinction of the Spanish Habsburg dynasty (1516-1700). This is the conclusion of research reported in an April 15 article in PLoS. The Spanish Habsburg dynasty was characterized by the frequent marrige of close relatives, in such a way that uncle-niece, first cousin, and other consanguineous unions were common. The dynasty ended with the childless death of the physically and mentally disabled Charles II at the age of 39. [PLoS article]

Molecular Switch Inhibition May Aid Treatment of Deadly Brain Cancers

Inhibition of the expression of a gene called NHERF-1 may be useful in the treatment of deadly brain cancers in the class glioblastoma multiforme (GBM), according to findings published by researchers at the Translational Genomics Research Institute (TGen) and Barrow Neurological Institute in the April issue of Neoplasia. "Our findings suggest a novel mechanism defining NHERF-1 as a 'molecular switch' that regulates the GBM tumor cell's ability to migrate or divide,'' said Dr. Kerri Kislin, the lead author of the study. The findings will be presented during the AACR annual meeting April 18-22. [Press release]

MicroRNAs May Improve Hearing

The lack of certain critical microRNAs can result in deafness, according to findings published in the April 14 issue of PNAS. "The molecules we identified could be used as a molecular tool delivered directly into the ears of deaf people to induce regeneration of important sensory cells that would improve hearing," one of the reporting researchers said. "The molecules also could potentially help people with balance disorders related to inner ear function such as Meniere's disease." Approximately 36 million Americans suffer from some form of hearing loss. In many cases, the cause is the degeneration of special sensory cells in the inner ear called hair cells. Excessive noise, certain medications, aging, and disease can damage or destroy hair cells. Because humans are unable to replace lost hair cells, hearing declines as they are lost. The researches identified specific microRNAs that are critical to the survival of hair cells. [Press release]

New Nucleotide Discovered in Mammals; May Revolutionize Epigenetics

Scientists at Rockefeller University have discovered a new methylated nucleotide in mammals. This discovery may revolutionize the study of epigenetics--i.e., inheritance not governed strictly by the sequence of nucleotides in a gene. The new methylated nucleotide (5-hydroxymethylcytosine) had previously been observed only in bacterial viruses. The Rockefeller researchers report that the new nucleotide is stable and abundant in mouse and human brain. The results are reported online in Science on April 16. [Press release]

Red Pandas Can Taste Artificial Sweetener

In a surprise finding, researchers at the Monell Chemical Senses Center have shown that a non-primate mammal (the red panda) can taste the articifial sweetener aspartame. Previously, only primates were believed able to taste this sweetener. The findings may shed light on how taste preferences and diet choice are shaped by molecular differences in taste receptors. [Press release]

Magnets Might Enable Low-Cost Nanopore DNA Sequencing

A novel technique to move DNA strands through nanopores at a slow enough speed for accurate sequencing has been developed by physicists at Brown University. The techique involves the use of "magnetic tweezers" in conjunction with an electric field to move the DNA. The researchers believe that this new technique might serve as the basis for lower-cost DNA sequencing. The research was reported in the journal Nanotechnology. [Press release]

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