hUNC93B1: a novel human gene representing a new gene family and encoding an unc-93-like protein

We have identified a novel human gene UNC93B1 encoding a protein related to unc-93 of Caenorhabditis elegans. The combined sequence derived from several cDNA clones is 2282 bp and comparison with genomic sequence shows that the gene contains 11 exons. The longest open reading frame encodes a deduced sequence of 597 amino acids. Homology analysis shows that the hUNC93B1 gene is highly conserved and related to sequences in Arabidopsis thaliana, C. elegans, Drosophila melanogaster, chicken and mouse. Structural analysis of the deduced amino acid sequence of hUNC93B1 points to possible existence of multiple membrane-spanning domains. hUNC93B1 protein also displays some similarities to the bacterial ABC-2 type transporter signature and to ion transporters of Deinococcus radiodurans and Helicobacter pylori. As revealed by Northern analysis, the level of expression varies significantly between tissues, with the highest level detected in the heart. The gene was mapped to chromosomal band 11q13 by fluorescence in situ hybridization. We suggest that this gene is a member of a novel hUNC93B-related gene family

A new approach to genome mapping and sequencing: slalom libraries

We describe here an efficient strategy for simultaneous genome mapping and sequencing. The approach is based on physically oriented, overlapping restriction fragment libraries called slalom libraries. Slalom libraries combine features of general genomic, jumping and linking libraries. Slalom libraries can be adapted to different applications and two main types of slalom libraries are described in detail. This approach was used to map and sequence (with ∼46% coverage) two human P1-derived artificial chromosome (PAC) clones, each of ∼100 kb. This model experiment demonstrates the feasibility of the approach and shows that the efficiency (cost-effectiveness and speed) of existing mapping/sequencing methods could be improved at least 5–10-fold. Furthermore, since the efficiency of contig assembly in the slalom approach is virtually independent of length of sequence reads, even short sequences produced by rapid, high throughput sequencing techniques would suffice to complete a physical map and a sequence scan of a small genome

NotI flanking sequences: a tool for gene discovery and verification of the human genome

A set of 22 551 unique human NotI flanking sequences (16.2 Mb) was generated. More than 40% of the set had regions with significant similarity to known proteins and expressed sequences. The data demonstrate that regions flanking NotI sites are less likely to form nucleosomes efficiently and resemble promoter regions. The draft human genome sequence contained 55.7% of the NotI flanking sequences, Celera’s database contained matches to 57.2% of the clones and all public databases (including non-human and previously sequenced NotI flanks) matched 89.2% of the NotI flanking sequences (identity ≥90% over at least 50 bp, data from December 2001). The data suggest that the shotgun sequencing approach used to generate the draft human genome sequence resulted in a bias against cloning and sequencing of NotI flanks. A rough estimation (based primarily on chromosomes 21 and 22) is that the human genome contains 15 000–20 000 NotI sites, of which 6000–9000 are unmethylated in any particular cell. The results of the study suggest that the existing tools for computational determination of CpG islands fail to identify a significant fraction of functional CpG islands, and unmethylated DNA stretches with a high frequency of CpG dinucleotides can be found even in regions with low CG content