Repressor synthesis in regulatory mutants of bacteriophage P22

1979 ◽  
Vol 167 (3) ◽  
pp. 337-339 ◽  
Author(s):  
A. M. Harvey ◽  
J. Heil ◽  
H. H. Prell





1978 ◽  
Vol 28 (3) ◽  
pp. 736-742 ◽  
Author(s):  
B Dasgupta ◽  
M Chakravorty
Keyword(s):  


Genetics ◽  
1979 ◽  
Vol 93 (3) ◽  
pp. 557-575
Author(s):  
Rowland H Davis

ABSTRACT A large number of arginine-requiring mutants of Neurospora was isolated, using a strain already partially impaired in an enzyme of the pathway. Among the mutants, all previously described loci, except one, were represented, and several new loci were defined and mapped. Four groups of mutants were of particular interest. First, thc large group of arg-6 mutants, when tested for intragenic complementation, suggested a bifunctional gene, possibly controlling two steps in ornithine synthesis. This is consistent with the limited enzymic information about this locus. Second, the arg-13 locus was represented by 14 new mutants. All five tested were quite leaky. suggesting that the function controlled by this gene can be rarried out to a limited extent spontaneously or by another gene product. Third, a new locus, arg-14, was defined. It controls a step in ornithine synthesis. It lies in a 1 to 2 map-unit interval between arg-2 and pyr-3 on LG IVR, as shown by mapping in relation tG translocation breakpoints. Fourth, a second new locus whose mutants render the partial mutation in starting material auxotrophic was defined and mapped near the centromere of LG VIL. These new mutants are unable to derepress enzymes of the pathway and may qualify as regulatory mutants.



Microbiology ◽  
2005 ◽  
Vol 151 (6) ◽  
pp. 1789-1800 ◽  
Author(s):  
Niamh Harraghy ◽  
Jan Kormanec ◽  
Christiane Wolz ◽  
Dagmar Homerova ◽  
Christiane Goerke ◽  
...  

Eap and Emp are two Staphylococcus aureus adhesins initially described as extracellular matrix binding proteins. Eap has since emerged as being important in adherence to and invasion of eukaryotic cells, as well as being described as an immunomodulator and virulence factor in chronic infections. This paper describes the mapping of the transcription start point of the eap and emp promoters. Moreover, using reporter-gene assays and real-time PCR in defined regulatory mutants, environmental conditions and global regulators affecting expression of eap and emp were investigated. Marked differences were found in expression of eap and emp between strain Newman and the 8325 derivatives SH1000 and 8325-4. Moreover, both genes were repressed in the presence of glucose. Analysis of expression of both genes in various regulatory mutants revealed that sarA and agr were involved in their regulation, but the data suggested that there were additional regulators of both genes. In a sae mutant, expression of both genes was severely repressed. sae expression was also reduced in the presence of glucose, suggesting that repression of eap and emp in glucose-containing medium may, in part, be a consequence of a decrease in expression of sae.





Author(s):  
Sherwood Casjens ◽  
Peter Weigele


1980 ◽  
Vol 140 (1) ◽  
pp. 129-142 ◽  
Author(s):  
Daniel DiMaio ◽  
Daniel Nathans


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