Expression of angiogenic factors in cryopreserved mouse ovaries after heterotopic autotransplantation.

Objective: Revascularization is critical for successful ovarian tissue transplantation. Vascular endothelial growth factor (VEGF) and angiopoietin-2 (angpt-2) are the principal mediators of neovascularization. This study was designed to assess VEGF and angpt-2 levels in cryopreserved ovarian tissue after heterotopic autotransplantation.

Interacting specificity of a histidine kinase and its cognate response regulator: the PrrBA system of Rhodobacter sphaeroides.

Using a yeast two-hybrid assay system, it was demonstrated that the four-helix bundle of the Rhodobacter sphaeroides PrrB histidine kinase both serves as the interaction site for the regulatory domain of its cognate response regulator PrrA and is the primary determinant of the interaction specificity. The alpha-helix 1 and its flanking turn region within the dimerization domain (DD) of the PrrB histidine kinase appear to play an important role in conferring the recognition specificity for the PrrA response regulator on the DD. The catalytic ATP-binding domain of the histidine kinase, which functions as the catalytic unit for the phosphotransfer reaction from ATP to the conserved histidine residue in the DD, also appears to contribute to the enhancement of the recognition specificity conferred by the DD.