Cloning and characterisation of the S.pombe rad15 gene, a homologue to the S.cerevisiae RAD3 and human ERCC2 genes

The RAD3 gene of Saccharomyces cerevisiae encodes an ATP-dependent 5' - 3' DNA helicase, which is involved in excision repair of ultraviolet radiation damage. By hybridisation of a Schizosaccharomyces pombe genomic library with a RAD3 gene probe we have isolated the S.pombe homologue of RAD3. We have also cloned the rad15 gene of S.pombe by complementation of radiation-sensitive phenotype of the rad15 mutant. Comparison of the restriction map and DNA sequence, shows that the S.pombe rad15 gene is identical to the gene homologous to S.cerevisiae RAD3, identified by hybridisation. The S.pombe rad15.P mutant is highly sensitive to UV radiation, but only slightly sensitive to ionising radiation, as expected for a mutant defective in excision repair. DNA sequence analysis of the rad15 gene indicates an open reading frame of 772 amino acids, and this is consistent with a transcript size of 2.6kb as detected by Northern analysis. The predicted rad15 protein has 65% identity to RAD3 and 55% identity to the human homologue ERCC2. This homology is particularly striking in the regions identified as being conserved in a group of DNA helicases. Gene deletion experiments indicate that, like the S.cerevisiae RAD3 gene, the S.pombe rad15 gene is essential for viability, suggesting that the protein product has a role in cell proliferation and not solely in DNA repair

Optimised determinisation and completion of finite tree automata

Determinisation and completion of finite tree automata are important operations with applications in program analysis and verification. However, the complexity of the classical procedures for determinisation and completion is high. They are not practical procedures for manipulating tree automata beyond very small ones. In this paper we develop an algorithm for determinisation and completion of finite tree automata, whose worst-case complexity remains unchanged, but which performs far better than existing algorithms in practice. The critical aspect of the algorithm is that the transitions of the determinised (and possibly completed) automaton are generated in a potentially very compact form called product form, which can reduce the size of the representation dramatically. Furthermore, the representation can often be used directly when manipulating the determinised automaton. The paper contains an experimental evaluation of the algorithm on a large set of tree automata examples

Property Testing via Set-Theoretic Operations

Given two testable properties $\mathcal{P}_{1}$ and $\mathcal{P}_{2}$, under what conditions are the union, intersection or set-difference of these two properties also testable? We initiate a systematic study of these basic set-theoretic operations in the context of property testing. As an application, we give a conceptually different proof that linearity is testable, albeit with much worse query complexity. Furthermore, for the problem of testing disjunction of linear functions, which was previously known to be one-sided testable with a super-polynomial query complexity, we give an improved analysis and show it has query complexity O(1/\eps^2), where \eps is the distance parameter.Comment: Appears in ICS 201

The N-terminal shuttle domain of Erv1 determines the affinity for Mia40 and mediates electron transfer to the catalytic Erv1 core in yeast mitochondria

Erv1 and Mia40 constitute the two important components of the disulfide relay system that mediates oxidative protein folding in the mitochondrial intermembrane space. Mia40 is the import receptor that recognizes the substrates introducing disulfide bonds while it is reduced. A key function of Erv1 is to recycle Mia40 to its active oxidative state. Our aims here were to dissect the domain of Erv1 that mediates the protein–protein interaction with Mia40 and to investigate the interactions between the shuttle domain of Erv1 and its catalytic core and their relevance for the interaction with Mia40. We purified these domains separately as well as cysteine mutants in the shuttle and the active core domains. The noncovalent interaction of Mia40 with Erv1 was measured by isothermal titration calorimetry, whereas their covalent mixed disulfide intermediate was analyzed in reconstitution experiments in vitro and in organello. We established that the N-terminal shuttle domain of Erv1 is necessary and sufficient for interaction to occur. Furthermore, we provide direct evidence for the intramolecular electron transfer from the shuttle cysteine pair of Erv1 to the core domain. Finally, we reconstituted the system by adding in trans the N- and C- terminal domains of Erv1 together with its substrate Mia40

Complementation in Spaces of Continuous Functions on Compact Lines

We characterize order preserving continuous surjections between compact linearly ordered spaces which admit an averaging operator, together with estimates of the norm of such an operator. This result is used to the study of strengthenings of the separable complementation property in spaces of continuous functions on compact lines. These properties include in particular continuous separable complementation property and existence of a projectional skeleton.Comment: 25 pages, One reference adde