Sp1 specifically binds to an evolutionarily conserved DNA segment within a region necessary for podocyte-specific expression of nephrin.

We have analyzed a conserved 237-bp segment located in a 1.9-kb upstream region of the nephrin gene, previously shown to contain kidney specific enhancer element(s). Electromobility shift assay was used to identify a 20-nucleotide region specifically recognized and bound by protein factors in nuclear extracts from immortalized podocyte and human embryonic kidney cell lines.

Overexpression of TIMP-1 under the MMP-9 promoter interferes with wound healing in transgenic mice.

We have generated transgenic mice harboring the murine matrix metalloproteinase 9 (MMP-9) promoter cloned in front of human TIMP-1 cDNA. The transgenic mice were viable and fertile and exhibited normal growth and general development. During wound healing the mice were shown to express human TIMP-1 in keratinocytes that normally express MMP-9.

Alternatively used promoters and distinct elements direct tissue-specific expression of nephrin.

Nephrin, an essential component of the glomerular ultrafilter, the slit diaphragm, has also been found to be expressed in the central nervous system and pancreas. This study examined the regulation of the nephrin gene by analyzing the expression of different length nephrin promoter-lacZ reporter constructs in transgenic mice. An upstream segment between -4 kb and -4 bp was shown to be sufficient for driving expression in all three tissues.