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This Week in PNAS: Feb 22, 2011

In the PNAS Early Edition this week, a public-private research collaboration among academicians and investigators at array technology vendors reports its development of a 6.9 million-feature oligonucleotide "human transcriptome array for high-throughput clinical studies." When compared to that of RNA-seq, the team says, this transcriptome array "allows comprehensive examination of gene expression and genome-wide identification of alternative splicing as well as detection of coding SNPs and non-coding transcripts," and it is "highly reproducible in estimating gene and exon abundance."

A team led by investigators at the University of Chicago reports on two cardiac-specific transcription factor genes, Smad4 and Gata4, that "cooperatively regulate cardiac valve development," online in PNAS this week. In their in vivo analysis, the team found that the genes interact — their endothelial-specific compound haploinsufficiency causes atrioventricular septal defects and Smad4 knockout causes "an absense of valve-forming activity" altogether. "We suggest that one determinant of the phenotypic spectrum caused by human GATA4 mutations is differential effects on GATA4/SMAD4 interactions required for endocardial cushion development," the authors write.

Researchers at the Marine Biology Laboratory in Woods Hole, Mass., led a team that reports "a combinatorial labeling strategy coupled with spectral image acquisition and analysis that greatly expands the number of fluorescent signatures distinguishable in a single image," which it used to differentiate 15 phylotypes in an E. coli community. This Combinatorial Labeling and Spectral Imaging FISH, or CLASI-FISH, approach uses "genus- and family-specific probes to differentiate phylotypes" in both lab-grown microbes and natural communities. Using CLASI-FISH, the team also reports "an initial systems-level structural analysis of biofilm organization."

Investigators at the University of Tokyo describe in PNAS the "structural basis for non-ribosomal peptide synthesis by an aminoacyl-tRNA synthetase paralog." More specifically, the team reports the crystal structures of "Bacillus licheniformis CDPS YvmC-Blic, in the apo form and complexed with substrate mimics," as well as its mutational and biochemical analyses, in which the researchers identified residues important to cyclodileucine formation and that "YvmC-Blic binds tRNA and generates cyclodileucine as a monomer."

The Scan

Pig Organ Transplants Considered

The Wall Street Journal reports that the US Food and Drug Administration may soon allow clinical trials that involve transplanting pig organs into humans.

'Poo-Bank' Proposal

Harvard Medical School researchers suggest people should bank stool samples when they are young to transplant when they later develop age-related diseases.

Spurred to Develop Again

New Scientist reports that researchers may have uncovered why about 60 percent of in vitro fertilization embryos stop developing.

Science Papers Examine Breast Milk Cell Populations, Cerebral Cortex Cellular Diversity, Micronesia Population History

In Science this week: unique cell populations found within breast milk, 100 transcriptionally distinct cell populations uncovered in the cerebral cortex, and more.