The previous study has shown that repeated D domain-like (Rdd) proteins, a group of novel secretory proteins consisting of repeated domains of a cysteine-rich sequence, are involved in the process of blood vessel formation in Xenopus embryo. We performed further experiments to examine the localization of Rdd proteins in embryogenesis. Detection of tagged Rdd proteins expressed in blastomeres showed that Rdd proteins formed a high molecular weight complex and existed in the extracellular space. A rabbit antibody against the Rdd synthetic peptide identified a single band of 28 kD in embryonic tissue extract. By whole-mount immunostaining analysis, signal was detected in the regions of inter-somites, vitelline veins, and branchial arches at the tailbud stage. Staining of Rdd was remarkably reduced in the embryos injected with vascular endothelial growth factor Morpholino. We suggest that Rdd proteins interact with a molecule(s) associated with vascular precursor cells.
Blastomeres ; Blood Vessels ; Branchial Region ; Embryonic Development ; Embryonic Structures* ; Extracellular Space ; Female ; Molecular Weight ; Pregnancy ; Vascular Endothelial Growth Factor A ; Veins ; Vitellins ; Xenopus*

1) A total of 60 medical and nursing student volunteers operated summer camps for 37 childhood cancer survivors treated at Mie University Hospital and for 51 members of their families in August, 2007 and 2008.2) A questionnaire survey (response rate, 81%; N=47) revealed that the students were seeking to make valuable contributions and to gain benefits for their future careers.3)The students were able to deepen their understanding of childhood cancer survivors and their families.