Regulation of amino acid assimilations in a strain of Neurospora crassa lacking basic amino acid transport activity

Thwaites, William M.; Pendyala, Lakshmi

doi:10.1016/0304-4165(69)90394-8

Cited by 35 publications

(21 citation statements)

References 9 publications

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“…Mutations which cause an alteration in basic amino acid transport specificity include bat (18), hlp-l (3), and strain CR-10 which is resistant to the arginine analogue canavanine (13). In addition to the permeases with charge specificity, a general amino acid transport system with very broad substrate specificity has been described in Neurospora and found to be present under certain conditions (10).…”

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confidence: 99%

Histidine Uptake in Strains of Neurospora crassa with Normal and Mutant Transport Systems

Magill,

Sweeney,

Woodward

1972

J Bacteriol

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Kinetic parameters for three systems of active histidine uptake by germinated conidia of Neurospora crassa have been measured. Each system appears to follow typical Michaelis-Menten kinetics when studied separately from the other systems. Under the conditions studied, the general amino acid transport system was found to account for the major portion of histidine uptake from low concentrations. Three types of transport mutants with altered growth inhibition patterns were selected in a histidine auxotroph. Growth of one mutant, type basa, could be inhibited by the addition of methionine to a histidine-supplemented medium, and another type, neua, could be inhibited by the addition of arginine. These mutants were shown to be lacking active histidine uptake by the basic amino acid and neutral amino acid transport systems, respectively. Another type of double mutant (his-3, neur) could be inhibited only by the addition of very high concentrations of methionine in the presence of arginine and histidine, and the mutation appeared to have altered the specificity of the neutral amino acid permease.on August 1, 2020 by guest

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confidence: 99%

Histidine Uptake in Strains of Neurospora crassa with Normal and Mutant Transport Systems

Magill,

Sweeney,

Woodward

1972

J Bacteriol

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“…We compared the transport of AIB in these two stages with that of the neutral amino acid L-citrulline, which had previously been proposed as a G system-specific substrate (11). Unlike AIB transport, citrulline transport was not eliminated by the pmg mutation and could only be eliminated by the addition of a second mutation, pmn.…”

Section: Resultsmentioning

confidence: 99%

“…We compared the specificity of AIB transport with that of the neutral amino acid L-citruline, which had previously been reported to be a general amino acid permease-specific substrate (11). In contrast to AIB, citrulline was transported by both the N and the G systems.…”

Section: Resultsmentioning

confidence: 99%

Characterization of 2-aminoisobutyric acid transport in Neurospora crassa: a general amino acid permease-specific substrate

Ogilvie-Villa¹,

DeBusk²,

DeBusk³

1981

J Bacteriol

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We report the characterization of an amino acid permease-specific substrate for Neurospora crassa. The neutral amino acid 2-aminoisobutyric acid was transported solely by the general amino acid permease and not by the neutral amino acid permease. Furthernore, this substrate was not metabolized after transport. The potential for a system-specific nonmetabolizable substrate as a tool in the analysis of amino acid transport and its regulation is discussed.Several laboratories have been involved with the analysis of amino acid transport in the fungus Neurospora crassa. The early goals of this research were to determine the number and types of systems which were responsible for transporting amino acids. This approach defined the strategy for amino acid transport by N. crassa as involving a limited number of constitutive permeases which transport families of structurally related amino acids: a neutral (N) system which is specific for neutral aliphatic or aromatic amino acids, a basic (B) system which transports positively charged amino acids, and a general (G) system which handles all classes of amino acids (1, 2, 4-7, 9-11, 14).Each family of amino acids is, therefore, transported both by the family-specific system and by the G system. Such overlap in substrate specificity between systems has made it difficult to ascribe particular properties to single systems. One approach to this problem involves the construction of mutant strains defective for the activity of one or more transport systems so that only the system of interest remains active. This approach has been very useful in defining the number of transport systems that exist and the physiological and kinetic properties of each. A second approach involves the identification and use of a system-specific amino acid substrate to monitor the activity of the permease of interest without eliminating the activities of the other perneases. This approach allows one to detect interactions among functional systems, an advantage not possible with the mutant approach. In addition, a permease-specific substrate is a useful tool, in combination with the mutant approach, for molecular studies of the components which comprise a particular transport system.We describe here the transport of the amino acid 2-aminoisobutyric acid (AIB) and its properties as a general amino acid permease-specific substrate. MATERLS AND METHODSStrains and growth of cultures. The wild-type strain 74a (FGSC 988) was obtained from the Fungal The pmn, pmb, and pmg strains are defective for the neutral amino acid-specific permease, the basic amino acid-specific permease, and the general amino acid permease, respectively, and are isogenic with the wild type. Each of these strains is available from the authors. All strains were maintained in lx Vogel medium N supplemented with 2% sucrose and solidified with 1.5% agar as previously described (2,13).Amino acid transport assays. For the conidial assays, cells were incubated at 25°C (0.1 mg of dry weight per ml of incubation medium, final concentration) in lx Vog...

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“…Mutations at the mtr locus confer resistance to 4-methyltryptophan (Lester, 1965;Stadler, 1966). Resistance to lcanavanine was used to identify the pmb locus (Pall, 1970;Thwaites and Pendyala, 1969). The pmg Ϫ strain, which lacks system II, was obtained by selecting for resistance to p-flurophenylalanine (FPA) in the pmb Ϫ , mtr Ϫ doublemutant strain (Rao et al, 1975).…”

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confidence: 99%

Identification of the Gene at the pmg Locus, Encoding System II, the General Amino Acid Transporter in Neurospora crassa

Margolis-Clark

Hunt

Espinosa

et al. 2001

Fungal Genetics and Biology

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Regulation of amino acid assimilations in a strain of Neurospora crassa lacking basic amino acid transport activity

Cited by 35 publications

References 9 publications

Histidine Uptake in Strains of Neurospora crassa with Normal and Mutant Transport Systems

Histidine Uptake in Strains of Neurospora crassa with Normal and Mutant Transport Systems

Characterization of 2-aminoisobutyric acid transport in Neurospora crassa: a general amino acid permease-specific substrate

Identification of the Gene at the pmg Locus, Encoding System II, the General Amino Acid Transporter in Neurospora crassa

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