Creation of hydrophilic nitric oxide releasing polymers via plasma surface modification.

Herein, we describe the surface modification of an S-nitrosated polymer derivative via H2O plasma treatment, resulting in polymer coatings that maintained their nitric oxide (NO) releasing capabilities, but exhibited dramatic changes in surface wettability. The poly(lactic-co-glycolic acid)-based hydrophobic polymer was nitrosated to achieve a material capable of releasing the therapeutic agent NO. The NO-loaded films were subjected to low-temperature H2O plasma treatments, where the treatment power (20-50 W) and time (1-5 min) were varied. The plasma treated polymer films were superhydrophilic (water droplet spread completely in <100 ms), yet retained 90% of their initial S-nitrosothiol content. Under thermal conditions, NO release profiles were identical to controls. Under buffer soak conditions, the NO release profile was slightly lowered for the plasma-treated materials; however, they still result in physiologically relevant NO fluxes. XPS, SEM-EDS, and ATR-IR characterization suggests the plasma treatment resulted in polymer rearrangement and implantation of hydroxyl and carbonyl functional groups. Plasma treated samples maintained both hydrophilic surface properties and NO release profiles after storage at -18 °C for at least 10 days, demonstrating the surface modification and NO release capabilities are stable over time. The ability to tune polymer surface properties while maintaining bulk properties and NO release properties, and the stability of those properties under refrigerated conditions, represents a unique approach toward creating enhanced therapeutic biopolymers.

Analysis of candidate genes in the CLN6 critical region using in silico cloning.

CLN6, the gene for variant late infantile neuronal ceroid lipofuscinosis, was mapped to a 4 cM region on chromosome 15q22-23. Subsequently the critical region was narrowed to less than 1 cM between microsatellite markers D15S988 and D15S1000 by additional marker typing in an expanded family resource. A physical map was constructed across this region using YAC and PAC clones and sequence was generated from two PAC clones. This sequence was analysed together with overlapping sequence generated by the Human Genome Project to identify genes within the region using an in silico cloning approach. In all, 29 genes have been identified and 18 have been analysed for mutations by direct sequencing. This powerful new approach will lead to the identification of CLN6.

Structure of the highly conserved HERC2 gene and of multiple partially duplicated paralogs in human.

Recombination between chromosome-specific low-copy repeats (duplicons) is an underlying mechanism for several genetic disorders. Recently, a chromosome 15 duplicon was discovered in the common breakpoint regions of Prader-Willi and Angelman syndrome deletions. We identified previously the large HERC2 transcript as an ancestral gene in this duplicon, with approximately 11 HERC2-containing duplicons, and demonstrated that recessive mutations in mouse Herc2 lead to a developmental syndrome, juvenile development and fertility 2 (jdf2). We have now constructed and sequenced a genomic contig of HERC2, revealing a total of 93 exons spanning approximately 250 kb and a CpG island promoter. A processed ribosomal protein L41 pseudogene occurs in intron 2 of HERC2, and putative VNTRs occur in intron 70 (28 copies, approximately 76-bp repeat) and 3' exon 40 through intron 40 (6 copies, approximately 62-bp repeat). Sequence comparisons show that HERC2-containing duplicons have undergone several deletion, inversion, and dispersion events to form complex duplicons in 15q11, 15q13, and 16p11. To further understand the developmental role of HERC2, a highly conserved Drosophila ortholog was characterized, with 70% amino acid sequence identity to human HERC2 over the carboxy-terminal 743 residues. Combined, these studies provide significant insights into the structure of complex duplicons and into the evolutionary pathways of formation, dispersal, and genomic instability of duplicons. Our results establish that some genes not only have a protein coding function but can also play a structural role in the genome.