Linked Life Data

1103873

Source:http://linkedlifedata.com/resource/pubmed/id/1103873

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1976-1-26
pubmed:abstractText
Radiation sensitivity in the fungus Neurospora crassa is under the control of at least eight distinct loci and is also affected by cytoplasmic factors. Although radiation-sensitive mutants which affect inter- or intragenic meiotic recombination have not been isolated, mutants which are defective in the repair of pyrimidine dimers have been found. Evidence from both mutational and biochemical studies shows that Neurospora has an excision-repair system for pyrimidine dimers which is very similar to the one found in Escherichia coli. Wild-type strains excise dimers, but two mutants, uvs2 and upr1, are UV sensitive and excision defective. Like the E. coli excision-defective mutants, the Neurospora mutants show a greatly increased frequency of UV-induced mutation at low UV doses, and they do not affect recombination. However, they differ from the E. coli mutants in being significantly more sensitive to ionizing radiation than wild-type strains. A third mutant, uvs6, resembles the DNA polymerase-I-negative mutants of E. coli. It is sensitive to both UV and X-irradiation, has a wild-type pattern of UV-induced mutation, and increases spontaneous deletion frequencies. Its polymerases have not been examined. The high frequency of UV-induced mutation in excision-defective strains suggests that a "mutation prone" system of DNA repair exists in Neurospora. This is supported by the ppoperties of the uvs3 strain, which shows no UV-induced mutation. Like postreplication-repair-defective E. coli mutants, it is UV and ionizing radiation sensitive and sensitive to both monofunctional and bifunctional alkylating agents. This mutant is sterile. As expected, the double mutant uvs3 upr1 strain is much more sensitive to UV than either single-mutant strain. Two other loci, muc2 and gs6, may affect DNA repair. Mutations at the five remaining loci, uvs1, uvs4, uvs5, gs3, and gs20, lead to a constellation of properties unlike those of any DNA-repair-deficient E. coli mutant. The occurrence of these mutations could mean that other DNA repair systems exist in Neurospora, or, like the lon mutants of E. coli, they might indicate that cell sensitivity to radiation damage can be increases in other ways.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0090-5542
pubmed:author
pubmed:issnType
Print
pubmed:volume
5B
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
567-76
pubmed:dateRevised
2009-10-27
pubmed:meshHeading
pubmed:year
1975
pubmed:articleTitle
Genetic control of radiation sensitivity and DNA repair in Neurospora.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Review