Differential chromosomal and mitochondrial DNA synthesis in temperature-sensitive mutants ofUstilago maydis |
| |
Authors: | P Unrau |
| |
Institution: | (1) N.I.M.R., The Ridgeway, Mill Hill, NW7 1AA London;(2) Present address: Biology and Health Physics Division, Chalk River Nuclear Laboratories, Atomic Energy of Canada Limited, KOJ 1JO Chalk River, Ontario, Canada |
| |
Abstract: | Summary The amount and type of residual DNA synthesis was determined in eight temperature-sensitive mutants of the smut fungusUstilago maydis after incubation at the restrictive temperature (32° C) for eight hours. Mutantsts-220,ts-207,ts-432 andts-346 were found to have an overall reduction in the synthesis of both nuclear and mitochondrial DNA in comparison to the wild-type.
In mutantsts-20,tsd 1-1,ts-84 andpol 1-1 nuclear DNA synthesis was depressed relative to mitochondrial synthesis. The DNA-polymerase mutantpol 1-1 had persistent nuclear synthesis at about 50% of the rate of synthesis of mitochondrial DNA and similar behavior was
observed in a diploid homozygous strain. Mutantts-84 had an initial burst of DNA synthesis which was reduced for nuclear but not mitochondrial synthesis after three hours
preincubation at 32°C.tsd 1-1 andts-20 had nuclear residual synthesis amounting to about 25% of the relative rate of mitochondrial synthesis with correlates
to increasing UV sensitivity of these strains on incubation at 32° C. Apol 1-1ts-84 double mutant had an additive loss of nuclear DNA synthesis which indicates that the steps of replication involved may
be sequential. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|