Hox genes and kidney patterning.
OBJECTIVE
Hox gene activity is essential for proper organization or pattern of the vertebrate body plan and is necessary for organogenesis. Sequence conservation within this family of genes is high yet they are involved in very diverse developmental processes. How this family functions in these processes is a challenging question, but is important for the understanding of renal organogenesis. Multiple Hox genes are expressed in the kidney and mutation in at least one group of paralogous genes results in severe renal defects.


RESULTS
Recent studies in mice with targeted Hox gene mutations and in kidney cell lines demonstrate that these genes have evolved to control tissue specific functions through their ability to regulate the expression of renal morphogens. The studies also demonstrate that Hox gene activity is not only restricted by the domain of expression but also by the specificity of the DNA binding homeodomain. Interestingly, these conserved homeodomains are not wholly interchangeable for normal renal organogenesis while they do appear to be interchangeable for axial skeleton development.


CONCLUSIONS
It is clear that Hox genes regulate important interactions between the ureteric bud and metanephric mesenchyme. Nevertheless, much work remains to define the expression patterns of multiple Hox genes during kidney development, to better determine the functional relationships of the encoded proteins, and to identify additional Hox downstream targets.
Patterson
Larry T
LT
Division of Nephrology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
Potter
S Steven
SS
D000818:Animals; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D007668:Kidney / Q000254:growth & development / Q000502:physiology*; D009154:Mutation / Q000235:genetics / Q000502:physiology
D018398:Homeodomain Proteins