1. ¹Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
2. ²Department of Mathematical Science, Chalmers University of Technology, Göteborg, Sweden
3. ³Department of Medical Biochemistry, Göteborg University, Göteborg, Sweden
4. ⁴Department of Medicine, Karolinska Institutet, Stockholm, Sweden

Correspondence: C Betsholtz, Department of Medicine, Karolinska Institutet, SE 171 77 Stockholm, Sweden. E-mail: christer.betsholtz@ki.se

⁵Current address: Department of Clinical Cell Biology and Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Japan

Received 31 July 2006; Revised 15 December 2006; Accepted 9 January 2007; Published online 28 February 2007.

Abstract

The kidney glomerulus plays a crucial role in blood filtration but the molecular composition and physiology of the glomerulus is not well understood. We previously constructed and large-scale sequenced four mouse glomerular expressed sequence tag (EST) libraries from newborn and adult mouse glomeruli. Here, we compared glomerular EST profiles with whole kidney EST profiles, thereby identifying 497 transcripts corresponding to UniGene clusters that were glomerulus-enriched, that is expressed more abundantly in glomeruli than in whole kidney. These include several known protein-coding glomerulus-specific transcripts critical for glomerulus development and function, but also a large number of gene transcripts, which have not previously been shown to be expressed in the glomerulus, or implicated in glomerular functions. We used in situ hybridization to demonstrate glomerulus-specific RNA expression for six novel glomerular genes and the public Human Protein Atlas to verify glomerular protein expression for another two. The higher mRNA abundance for the eight genes in glomeruli compared with whole kidney was also verified by Taqman quantitative polymerase chain reaction. We surmise that the further characterization of these genes and proteins will increase our understanding of glomerular development and physiology.