Neurospora crassa qa-2 gene fragment.

This is the authors' abstract. We don't add key points for this paper.

Neurospora crassa qa-2 gene fragment.This research note is available in Fungal Genetics Reports: https://newprairiepress.org/fgr/vol30/iss1/5In an effort to isolate the aro cluster-"ene (Gaertner Morse, C.C., R. Manger and F. Gaertner and Cole 1977 Biochem.Biophys.Res.Commun.75: 259) from N. crassa, we prepared a total BamHI digest of chromosomal DNA, ligated into the Saccharomyces shuttle vector pYE13 (Broach et at.1979 Gene 8: 121), and amplified the resultant genomic library in E. coli (Procedure I).The amplified genebank was used to attempt complementation in four mutants of E. coli (see E. coli strains lacking aro activities by transformation (Procedure II).Only the E. coli mutant SK288a (aroD), which lacks DHQase, was complemented.Isolation of plasmid DNA (Procedure III), and subsequent restriction of the DNA with BamHI, showed that the complementing activity was present on a 3.2 kbp BamHI fragment.This fragment in pYE13 also complements the qa-2 gene of N. crassa (Case and Giles, personal communication), but does not complement DHQase minus strains of Saccharomyces cerevisiae (our unpublished results).Subcloning of the 3.2 kbp insert was performed to obtain both orientations within the pYE13 shuttle-vector.Complementation was observed in the E. coli, aroD, mutant in both orientations, indicating that promoter activity was inherent to the fragment and independent of plasmid promoter functions.Enzyme preparations from the complemented E. coli aroD mutant also confirmed the existence of the qa-2 gene on the 3.2 kbp fragment.Thus, we concluded that the 3.2 kbp BamHI fragment from Neurospora crassa carried the structural and promoter information of the qa-2 dehydroquinase gene.Complementing activities for other E. coli aro mutations relevant to the aro cluster-gene have not been observed, suggesting either that BamHI cuts and inactivates these genes, or that some incompatibility exists between E. coli and N. crassa with respect to these genetic elements.