Studies suggest that the pivotal role of WT-1 is to induce the ureteric bud
and METs.[sup],, Only Pax2 and Pax8 of the Pax gene family express in the developing kidney.[sup] The expression of the Pax2 and Pax8 genes is mainly distributed in the period of renal capsule body, coma-shaped body, and S-shaped body, which suggests their role in cell proliferation.
Kusano, "Low ambient [O.sub.2] enhances ureteric bud
branching in vitro," Organogenesis, vol.
The researchers then guided these cells to further differentiated into organ structures similar to those found in the ureteric bud
by culturing them with kidney cells from mice.
The Salk findings demonstrate for the first time that pluripotent stem cells (PSCs)-cells capable of differentiating into the many cells and tissue types that make up the body- can made to develop into cells similar to those found in the ureteric bud
, an early developmental structure of the kidneys, and then be further differentiated into three-dimensional structures in organ cultures.
The aetiology is unclear, although it is hypothesised that the problem lies with the ureteric bud
crossing over to the contralateral metanephric blastema, thereby inducing differentiation of a renal promordium.4
Similar findings were reported earlier in which development of the collecting duct system was greatly impaired in RAR ab2- mutant mice embryo; fewer branches of ureteric bud
were present, and their ends were positioned abnormally at a distance from the renal capsule (Mendelsohn et al., 1999).
The kidney derives from the nephric ridge of the intermediate mesoderm where the pro-nephric duct elongates to form the Wolffian duct, which in turn gives rise to the ureteric bud
and sets the stage for condensation of metanephric mesenchyme and mesynchemal-to-epithelial cell transition.
This is thought to result from the abnormal development and migration of the ureteric bud
and metanephric blastema during the fourth week to eighth week of gestation.