Temperature-sensitive mutations in Drosophila melanogaster,I. Relative frequencies among gamma-ray and chemically induced sex-linked recessive lethals and semilethals.

Abstract

Genetic and biochemical analysis in microorganisms has been greatly facilitated by the use of conditional lethal mutations that die under "restrictive" conditions but survive in a "permissive" environment." 2 One class of conditional lethals, the temperature-sensitive (ts) mutants that result from a single amino acid substitution that renders a polypeptide inactive at high temperatures,3-5 has been extensively analyzed in Neurospora,6 bacteria,7 T4 phages,"8 and tobacco mosaic virus.3 4 In higher organisms, ts mutants have been detected in Arabidopsis,9 Paramecium,'0 and Drosophila. II The potential usefulness of ts mutants in several types of genetic analyses prompted us to screen for them systematically in Drosophila melanogaster. This paper reports the frequencies of ts mutants among sex-linked recessive lethals and semilethals induced by Py-rays, ethyl methanesulfonate, and mitomycin C. Methods and Materials.-Screening technique: Oregon-R males were collected within 48 hr of eclosion, treated as described below, and then mated separately with three Basc females in vials at room temperature (230 1 20C). The males were transferred without etherization to a fresh set of females at 2-day intervals for several consecutive broods. Each set of females was removed from the vials 3 days after transfer of the males in the experiments with mitomycin C and y-rays. Owing to the poor fertility of males treated with ethyl methanesulfonate, females in these experiments were allowed to lay eggs for up to 5 days after transfer of the males and in some cases were then transferred to a fresh vial. Single F, females from each brood of each male were placed together with one or two Basc males at 290 ± 0.50C. The presence of two or less non-Basc F2 males in a fertile culture suggested that a lethal or semilethal had been induced on the X chromosome. Replicate cultures of the F2 of all possible lethals and semilethals were set at-290C and

Cloning by function: an alternative approach for identifying yeast homologs of genes from other organisms.

“…An important advantage of this screen is that any lethal mutation in the gene of interest would be recovered: there is no requirement for conditional-lethal mutations, which are much rarer than simple null mutations (29). Furthermore, screens for conditional-lethal mutations are not inclusive because screens for thermal sensitive, 2H20-sensitive, and ochre mutations yielded many mutations in nonoverlapping genes (9,30).…”

Temperature-sensitive mutations inHabrobracon

“…As one might expect, and as other investigators have found (Suzuki et al 1967), many mutants are 'leaky' and/or show pleiotropism. Although many tsl mutants are simple to maintain in the laboratory, otbers are not.…”

“…Temperature-sensitive mutations have been induced in insects by mutagens and are now being used for various genetic and developmental studies: in Drosophila (Suzuki et al 1967;Baillie, Suzuki & Tarasoff, 1968;Suzuki & Procunier, 1969;Tarasoff & Suzuki, 1970;Suzuki, 1970;Hotta & Benzer, 1970, 1972; Habrobracon (Smith, 1968(Smith, , 1969; and Musca (McDonald, 1972). In addition, conditional lethals have been postulated to be useful in the control of insect populations (Smith & von Borstel, 1972).…”

Effect of the Inhibition of Nucleic Acids and Protein Synthesis upon the Development of Melanotic Tumors in <i>Drosophila</i>

“…It operates by cross-linking the complementary strands of DNA and may cause chromosome aberrations [6]. In Dro sophila, mitomycin C increases the frequency of crossing-over [27], of recessive mutations [28], and of chromosome aberrations [29]. It should therefore be able to induce tumoral transformation of somatic cells.…”