FGSC #3781

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Reporting Genes: un(6T);inl

Species: crassa

Allele: 6T(t);89601

Alternate Strain Number: 6T

Mutagen: UV

Depositor: DRS

Linkage Group: IR;VR

Mating Type: a

Species Number: 10

Genetic Background: M

Deposit Sheet ↗

Genes

Locus	Cultural Requirements	Link Group	Type
un(6T)	Unknown function. Temperature-sensitive (heat-sensitive) conditional mutants, irreparable by supplementation at the restrictive temperature (usually 34 to 37 C). Originally referred to as "unknown requirement" on the initial hypothesis that such mutants would prove to be auxotrophs. Several heat- sensitive genes have been sufficiently characterized to be assigned more specific names than un (e.g., ndc, rip, psi, eth-1, and fs-2). At least some unmutants are deficient in amino acid transport (543, 1075). For most un loci, however, little is known of the molecular or cellular basis. Because of their map locations, several are useful as genetic markers. Scoring may require growth comparisons at two temperatures, preferably with small conidial inocula. Some heat-sensitive mutants with altered morphology at restrictive temperature are called cot or scot. Temperature-sensitive auxotrophs with certain requirements have sometimes been classed initially as un because complex complete medium is either inadequate or inhibitory. Thus, complex-medium-irreparable temperature-sensitive mutants no. 3, 13, and 14 of reference 507 proved to be temperature-sensitive thr auxotrophs; no. 6, 20, and 30 were his; and no. 19, 24, and 35 were asn(T. Ishikawa, personal communication). Many un mutants do not achieve normal growth rates even at the permissive temperature (usually 25 C). Genes un-1 to un-8 were assigned locus numbers in reference 813. "T" in allele numbers of several un mutants designates Tokyo, not translocation.		B
inl	VR. Between pho-3 (3 to 4%) and pab-1 (1 to 10%). Right of al-3 (362, 397, 1036). (482)Requires inositol (65). Lacks D-myoinositol-1-phosphatase (1142). Lack of glucocycloaldolase found by Pina and Tatum (826) is attributed by Williams (1142) to drastic repression of glucocycloaldolase by the concentration of inositol used for growth. Growth is colonial on low levels of inositol (367). Tends to extrude dark pigment into the medium when grown on suboptimal inositol. Composition of phospholipids and cell walls is abnormal on limiting inositol (367, 439, 440, 501). Inhibited by hexachlorocyclohexane (366, 457, 931). Conidia are subject to death by unbalanced growth on minimal medium (1028, 1033), a property exploited for mutant enrichment ("inositol-less death") (606, 647) because double mutants are at a selective advantage. Heat-sensitive allele 83201 is especially useful for mutant enrichment (832, 1043). Used in the first experiments reporting transformation of Neurospora by N. crassaDNA (677, 679) and reported to be efficient as a recipient in absence of inositol (1162). Used to study glucose (917) and sulfate (641) transport systems. Used extensively for studying induced reversion (392). Used for studying the mechanism of inositol-less death (647, 702), mutagenicity of ferrous ions, and regulation of mitochondrial membrane fluidity; for a review, see reference 702. Spontaneous reversion rates (386). Allele-specific partial suppressor (390). Allele 46802 is nonrevertable and inseparable from translocation 46802 (386, 808). Strains carrying heat-sensitive allele 83201 show slow semicolonial growth in liquid minimal medium at 25°C (641), but look normal on slants (D.D. Perkins, unpublished data). Strains carrying allele 89601 contain cross-reacting material (1183). Mutant gene exo-1 is present in the inl(89601) a stock FGSC 498 and may, therefore, be present in stocks of mutants derived by inositol-less death. (See references 194, 325, and 1027). Called inos.	VR	B