Gene transfer

Human ROSA26 locus

The ROSA26 locus in the genome of mouse embryonic stem cells is easy to target and expresses transgenes well. Irion et al. identified the human equivalent of the ROSA26 locus on chromosome 3. They integrated various genes into that locus and followed the multilineage differentiation of the targeted cells. Their locus provides a safe landing spot for transgenes and makes worries about gene silencing or disruption of endogenous genes because of random integration a thing of the past.

Irion, S. et al. Nat. Biotechnol. 25, 1477–1482 (2007).

Immunochemistry

High-throughput antibodies

Antibodies are key reagents for the study of protein function. Schofield et al. now screen a phage display library to identify human monoclonal antibodies on an unprecedented scale. They identified antibodies to 72% of 404 antigen targets, with an average of 25 specific clones to each. As with all high-throughput efforts, quality control and validation are key elements of the work.

Schofield, D.J. et al. Genome Biol. 8, R254 (2007).

Stem cells

Fingerprinting stem cells

Haematopoetic stem cells differentiate to give rise to all the cells in the blood. By performing global gene expression analysis on these cells and on their differentiated progeny, Chambers et al. identified molecular fingerprints for specific cell types and cell lineages in the blood. This resource will be useful for developing markers and for identifying regulators of differentiation and cell fate specification in haematopoesis.

Chambers, S.M. et al. Cell Stem Cell 1, 578–591 (2007).

Chemistry

Synthetic lectins

Lectins are highly specific carbohydrate receptors that are being increasingly applied as tools for carbohydrate detection. Ferrand et al. designed a synthetic lectin analog that can recognize the disaccharide cellobiose with very high affinity and specificity. As the analog is much smaller than natural lectins, this represents notable progress toward the design of synthetic carbohydrate receptors for practical use as sensors.

Ferrand, Y. et al. Science 318, 619–622 (2007).

Imaging and visualization

Single-molecule tracking by fours

The need to track single fluorescently labeled proteins in living cells has created a desire for three-dimensional single-particle tracking methods using low-level illumination. Lessard et al. show that they can track single quantum dots using only 10 μW of energy by using four optical fibers coupled to individual detectors to effectively create four confocal pinholes that provide location information for feedback control–based tracking.

Lessard, G.A. et al. Appl. Phys. Lett. 91, 224106 (2007).