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.