The Neurospora uvs-2 gene encodes a protein which has homology to yeast RAD18, with unique zinc finger motifs

A clone containing the DNA repair gene uvs-2 of Neurospora crassa was identified from a Neurospora genomic DNA library using the sib-selection method. Transformants were screened for resistance to methyl methane sulfonate (MMS). A DNA fragment that complements the uvs-2 mutation was subcloned by monitoring its ability to transform the uvs-2 mutant to MMS resistance. Deletion analysis of the cloned DNA indicated that the size of the uvs-2 gene is approximately 1.6 kb. The identity of the uvs-2 gene was verified by restriction fragment length polymorphism (RFLP) mapping. The sensitivity of the transformant to three different mutagens was similar to that of the wild-type strain. Nucleotide sequences of genomic DNA and cDNA of the uvs-2 gene indicated that it has an open reading frame (ORF) of 1572 bp with a 69 bp intron in the middle of the sequence. Two transcription initiation sites located around 73 bp and 290 bp upstream of the translation initiation codon were identified by primer extension experiments. Northern analysis revealed that the nature transcript of the uvs-2 gene was about 1.8 kb long. The uvs-2 gene ORF is deduced to encode a polypeptide of 501 amino acids with a molecular mass of 54 kDa. The proposed polypeptide has 25% identity to the RAD18 polypeptide of Saccharomyces cerevisiae and contains two unique zinc finger motifs for nucleic acid binding. Similarities between the phenotypes of the rad18 and uvs-2 mutants suggest that the uvs-2 gene encodes a protein which is involved in postreplication repair, rather than excision repair.

The mus-8 gene of Neurospora crassa encodes a structural and functional homolog of the Rad6 protein of Saccharomyces cerevisiae

We cloned a DNA repair gene, mus-8, of Neurospora crassa and sequenced the genomic DNA and cDNA. Nucleotide-sequence analysis indicated that the mus-8 gene contains an open reading frame (ORF) of 456 bp, interrupted by three small introns. The deduced amino-acid sequence showed that the mus-8 gene encodes a 17 kDa protein which has 77.5% and 83.3% identity to the Rad6 protein of Saccharomyces cerevisiae and the rhp6(+) protein of Schizosaccharomyces pombe, respectively. The Rad6 protein is a ubiquitin-conjugating enzyme (E2) and is required for DNA repair, mutagenesis, and sporulation in yeast. Introduction of the mus-8 gene into a S. cerevisiae rad6 mutant resulted in significant recovery of DNA repair functions, especially UV-mutagenesis, and also sporulation, both of which are defective in the rad6 mutant. It is therefore postulated that mus-8 of Neurospora has a function very similar to that demonstrated for RAD6 of S. cerevisiae.

Percutaneous Cryoablation of Lower Limb Soft-Tissue Venous Malformations: Preliminary Results of Long-Term Efficacy

PURPOSE

To retrospectively evaluate long-term efficacy of percutaneous cryoablation for lower limb soft-tissue venous malformations.

MATERIALS AND METHODS

Nine patients (mean age, 36.6 years) with lower limb soft-tissue venous malformations were included. Cryoablation was performed percutaneously using an argon-based system. Adverse events (AE) using the Common Terminology Criteria for AEs version 4.0 were evaluated. The visual analog scale (VAS) scores and lesion volumes measured on magnetic resonance imaging were also evaluated at 12 months and 5-6 years.

RESULTS

Technical success (i.e., complete coverage of the lesion by an iceball) was achieved in eight of the nine patients. All patients developed a total of 14 grade 1 or 2 adverse events. The mean (± standard deviation) VAS score was 6.0 (± 1.7) before therapy, whereas it was 0.14 (± 0.27) at 12 months and 0.97 (± 1.3) at 5-6 years (58-78 months). Complete pain relief was obtained in 6 and 5 patients at 12 months and 5-6 years, respectively. The median lesion volume was 2.49 mL before therapy, whereas it was 0.26 mL at 12 months and 0.35 mL at 5-6 years.

CONCLUSION

Percutaneous cryoablation of lower limb soft-tissue venous malformations achieved considerable pain relief and lesion shrinkage for 5-6 years in this small preliminary study.

LEVEL OF EVIDENCE

Level 4, Case Series.