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This Week in PNAS: Nov 9, 2010

In the PNAS Early Edition this week, researchers at the University of Pennsylvania and their colleagues in China report their "reversal of pre-existing hyperglycemia" in streptozotocin-treated, diabetic mice via the "acute and temporally controlled excision of the Men1 gene, which encodes menin." In addition, the team shows than Men1 excision improved glucose metabolism and "upregulated a group of pro-proliferative genes in pancreatic islets," which they say supports the idea that "established hyperglycemia can be reversed through repression of a single gene, Men1."

In another paper published online in advance in PNAS, investigators at the National Cancer Institute show that methyl CpGs produce DNA binding sites at "half-CRE and half-C/EBP sequences for [the transcription factor] C/EBPα that are needed to activate tissue-specific genes." Using transfection assays, the NCI team found that "C/EBPα activates the CRE sequence only when it is methylated," which was biologically significant in "differentiating primary keratinocyte cultures from newborn mice where certain methylated promoters are both bound by C/EBPα and activated upon differentiation." In their subsequent cell culture transfections, the team found that half-CRE and half-C/EBP sequences must be methylated for C/EBPα-mediated activation.

A public-private research collaboration among researchers at Dow AgroSciences and the University of Missouri reports online in PNAS this week that aryloxyalkanoate dioxygenase transgenes confer "robust crop resistance to broadleaf and grass herbicides." The team found that maize plants transformed with an AAD-1 gene were resistant to aryloxyphenoxypropionate herbicides over four generations and were not harmed by 2,4-D applications. Arabidopsis plants expressing AAD-12, the authors show, "were resistant to 2,4-D as well as triclopyr and fluroxypyr," while "transgenic soybean plants expressing AAD-12 maintained field resistance to 2,4-D over five generations."

Researchers in Europe this week show that a "genetically encoded, specific, universal, and phenotypically neutral" dendritic marker, DenMark — which is a "hybrid protein of the mouse protein ICAM5/Telencephalin and the red fluorescent protein mCherry" — is a "powerful tool for revealing novel aspects of the neuroanatomy of developing dendrites, identifying previously unknown dendritic arbors, and elucidating neuronal connectivity" in Drosophila.

The Scan

Positive Framing of Genetic Studies Can Spark Mistrust Among Underrepresented Groups

Researchers in Human Genetics and Genomics Advances report that how researchers describe genomic studies may alienate potential participants.

Small Study of Gene Editing to Treat Sickle Cell Disease

In a Novartis-sponsored study in the New England Journal of Medicine, researchers found that a CRISPR-Cas9-based treatment targeting promoters of genes encoding fetal hemoglobin could reduce disease symptoms.

Gut Microbiome Changes Appear in Infants Before They Develop Eczema, Study Finds

Researchers report in mSystems that infants experienced an enrichment in Clostridium sensu stricto 1 and Finegoldia and a depletion of Bacteroides before developing eczema.

Acute Myeloid Leukemia Treatment Specificity Enhanced With Stem Cell Editing

A study in Nature suggests epitope editing in donor stem cells prior to bone marrow transplants can stave off toxicity when targeting acute myeloid leukemia with immunotherapy.