M Krüger

Publications (2)13.21 Total impact

• Source

  Available from: nih.gov

  Article: Integrity of a Zn finger-like domain in SamB is crucial for morphogenesis in ascomycetous fungi.

  M Krüger, R Fischer
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  ABSTRACT: Genetic features determine the site of polarized growth in filamentous fungi and lead to hyphal tip extension or subapical branching. We have isolated the samB gene (suppressor of anucleate metulae) of Aspergillus nidulans which encodes a 66 kDa protein carrying an atypical Cys4 and an additional Cys2/His/Cys Zn finger motif at the carboxy-terminus. Such novel Zn finger-like domains have recently been found in several other developmental regulators in organisms ranging from yeast to man. Deletion of this domain at the carboxy-terminus of SamB led to premature hyphal ramification, mislocalization of septa and suppression of the asporogenous phenotype of the developmental mutant aps (anucleate primary sterigmata). A DeltasamB deletion strain displayed an identical phenotype. A homologous gene in Saccharomyces cerevisiae was also characterized whose deletion resulted in a multi-budding phenotype; thus it was named MUB1. An underlying common mechanism for both genes in determination of the onset of polarized growth and its links to other cellular developmental processes is discussed.
  The EMBO Journal 02/1998; 17(1):204-14. · 9.20 Impact Factor
• Source

  Available from: genetics.org

  Article: Isolation of two apsA suppressor strains in Aspergillus nidulans.

  M Krüger, R Fischer
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  ABSTRACT: Aspergillus nidulans reproduces asexually with single nucleated conidia. In apsA (anucleate primary sterigmata) strains, nuclear positioning is affected and conidiation is greatly reduced. To get further insights into the cellular functions of apsA, aconidial apsA strains were mutagenized and conidiating suppressor strains were isolated. The suppressors fell into two complementation groups, samA and samB (suppressor of anucleate metulae), samA mapped on linkage group 1 close to pyrG. The mutant allele was dominant in diploids homozygous for apsA. Viability of conidia of samA suppressor strains (samA-; apsA-) was reduced to 50% in comparison to wild-type conidia. Eighty percent of viable spores produced small size colonies that were temperature and benomyl-sensitive. samB mapped to chromosome VIII and was recessive. Viability of conidia from samB suppressor strains (apsA-; samB) was also affected but no small size colonies were observed. Both suppressors produced partial defects in sexual reproduction and both suppressed an apsA deletion mutation. In wild-type background the mutant loci affected hyphal growth rate (samA) or changed the colony morphology (samB) and inhibited sexual spore formation (samA and samB). Only subtle effects on conidiation were found. We conclude that both suppressor genes bypass the apsA function and are involved in microtubule-dependent processes.
  Genetics 11/1996; 144(2):533-40. · 4.01 Impact Factor