Growth Hormone and Development

During development, genes are often transcribed in a temporally and spatially regulated manner. The murine growth hormone gene is differentially expressed in the developing pituitary gland. Lunyak et al. now examine the region surrounding the growth hormone gene and show that a repeated DNA sequence (short interspersed nuclear element B2) in the growth hormone locus functions as an insulator to produce a boundary for chromatin domains and limit the action of regulatory factors such as enhancers and silencers.

Source:

Developmentally Regulated Activation of a SINE B2 Repeat as a Domain Boundary in Organogenesis. Lunyak et al. Science 13 July 2007: Vol. 317. no. 5835, pp. 248 - 251.

Genome Transplantation in Bacteria: Changing One Species to Another

As a step toward propagation of synthetic genomes, we completely replaced the genome of a bacterial cell with one from another species by transplanting a whole genome as naked DNA. Intact genomic DNA from Mycoplasma mycoides large colony (LC), virtually free of protein, was transplanted into Mycoplasma capricolum cells by polyethylene glycol-mediated transformation. Cells selected for tetracycline resistance, carried by the M. mycoides LC chromosome, contain the complete donor genome and are free of detectable recipient genomic sequences. These cells that result from genome transplantation are phenotypically identical to the M. mycoides LC donor strain as judged by several criteria.

Source:

Genome Transplantation in Bacteria: Changing One Species to Another. Lartigue et al. Published Online June 28, 2007. Science DOI: 10.1126/science.1144622.