Functional conservation of Pax6 regulatory elements in humans and mice demonstrated with a novel transgenic reporter mouse.
BACKGROUND
The Pax6 transcription factor is expressed during development in the eyes and in specific CNS regions, where it is essential for normal cell proliferation and differentiation. Mice lacking one or both copies of the Pax6 gene model closely humans with loss-of-function mutations in the PAX6 locus. The sequence of the Pax6/PAX6 protein is identical in mice and humans and previous studies have shown structural conservation of the gene's regulatory regions.


RESULTS
We generated a transgenic mouse expressing green fluorescent protein (GFP) and neomycin resistance under the control of the entire complement of human PAX6 regulatory elements using a modified yeast artificial chromosome (YAC). Expression of GFP was studied in embryos from 9.5 days on and was confined to cells known to express Pax6. GFP expression was sufficiently strong that expressing cells could be distinguished from non-expressing cells using flow cytometry.


CONCLUSIONS
This work demonstrates the functional conservation of the regulatory elements controlling Pax6/PAX6 expression in mice and humans. The transgene provides an excellent tool for studying the functions of different Pax6/PAX6 regulatory elements in controlling Pax6 expression in animals that are otherwise normal. It will allow the analysis and isolation of cells in which Pax6 is activated, irrespective of the status of the endogenous locus.
Tyas
David A
DA
Genes and Development Group, Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK. tyas_d@hotmail.com
Simpson
T Ian
TI
Carr
Catherine B
CB
Kleinjan
Dirk A
DA
van Heyningen
Veronica
V
Mason
John O
JO
Price
David J
DJ