Wilms tumors (WTs) are genetically heterogeneous kidney tumors whose cells of origin are unknown. Tumors with WT1 mutations and concomitant loss of the wild-type allele represent a distinct subgroup, frequently associated with mutations in CTNNB1. Here, we describe the establishment and characterization of long-term cell cultures derived from five individual WTs with WT1 mutations. Three of these tumor cell lines also had CTNNB1 mutations and an activated canonical Wnt signaling pathway as measured by beta-catenin/T cell-specific transcription factor (TCF) transcriptional activity. Four of the five Wilms cell lines had a stable normal karyotype for at least 25 passages, and four lines showed loss of heterozygosity of chromosome 11p due to mitotic recombination in 11p11. Gene expression profiling revealed that the WT cell lines are highly similar to human mesenchymal stem cells (MSCs) and FACS analysis demonstrated the expression of MSC-specific surface proteins CD105, CD90 and CD73. The stem cell like nature of the WT cells is further supported by their adipogenic, chondrogenic, osteogenic and myogenic differentiation potentials. By generating multipotent mesenchymal precursors from paraxial mesoderm (PAM) in tissue culture using embryonal stem cells, gene expression profiles of PAM and MSCs were described. Using these published gene sets, we found coexpression of a large number of genes in WT cell lines, PAM and MSCs. Lineage plasticity is indicated by the simultaneous expression of genes from the mesendodermal and neuroectodermal lineages. We conclude that WTs with WT1 mutations have specific traits of PAM, which is the source of kidney stromal cells.

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Abstract.-The present paper describes the purification and properties of a glucuronosyltransferase isolated from 13-day embryonic chick brain. The enzyme catalyzes transfer of glucuronic acid from UDP-glucuronic acid to a series of low and high molecular weight compounds which contain terminal nonreducing f-D-galactose residues. Studies utilizing enzymatically degraded chondromucoprotein as acceptor suggest that the glucuronosyltransferase terminates biosynthesis of the linkage region between protein and polysaccharide of chondromucoprotein.A number of investigators have shown that naturally occurring mucopolysaccharides are covalently bound to protein.1-3 A common linkage region between protein and polysaccharide was demonstrated in several mucopolysaccharides including chondroitin sulfate,4-6 heparin,7' 8 and dermatan sulfate.9' 10

This research suggests that aliphatic PEG polymers can be used as a new method for increasing the activity of insecticidal proteins.