Telomere length homeostasis and telomere position effect on a linear human artificial chromosome are dictated by the genetic background.

Telomere position effect (TPE) is the influence of telomeres on subtelomeric epigenetic marks and gene expression. Previous studies suggested that TPE depends on genetic background. As these analyses were performed on different chromosomes, cell types and species, it remains unclear whether TPE represents a chromosome-rather than genetic background-specific regulation.

Apoptosis affects integration frequency: adult stem cells injected in blastocysts show high caspase-3 activity.

Chimeric organisms are commonly generated by injecting stem cells into blastocysts. Embryonic stem cells injected into the blastocoel cavity participate in the further development of the embryo. Adult stem cells have also been used in injection experiments to study their potential plasticity.

Paraffin-embedded manipulated blastocysts: a tool to demonstrate stem cell plasticity?

One of the big question marks in current stem cell research is whether there is true plasticity of adult progenitor cells (APC) or if cell fusion is the principle source of the supposed plasticity. The generation of chimeras by injecting adult progenitor cells into blastocysts is not new. This paper describes an efficient embedding technique for murine blastocysts injected with human APC.

Breaking the species barrier: derivation of germline-competent embryonic stem cells from Mus spretus x C57BL/6 hybrids.

Embryonic stem (ES) cells, which can differentiate into almost all types of cells, have been derived from the house mouse Mus musculus, rat, rabbit, humans, and other species. Transmission of the genotype to the offspring of chimeras has been achieved only with M. musculus ES cells, limiting targeted mutagenesis using ES cells to this species.

The pituitary adenylate cyclase-activating polypeptide is a physiological inhibitor of platelet activation.

The pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide of the vasoactive intestinal peptide/secretin/glucagon superfamily. Studies in two related patients with a partial trisomy 18p revealed three copies of the PACAP gene and elevated PACAP concentrations in plasma. The patients suffer from severe mental retardation and have a bleeding tendency with mild thrombocytopenia, and their fibroblasts show increased PACAP mRNA levels.