Wood WB (1976) Worm Breeder's Gazette "maternal effects among ts zygote-defective (zyg) mutants."

Wood WB

[Worm Breeder's Gazette, 1976]

We have studied maternal effects in 23 zyg ts mutants to estimate the times of expression of genes whose products are required in embryogenesis. We have used the following three tests, called arbitrarily A, B, and C. A test: Heterozygous (m/+) L4's are shifted to 25 C and allowed to self-fertilize. If 100% of their eggs yield larvae (25% of which express the mutant phenotype as adults), then the mutant is scored as maternal (M). If 25% of the F1 eggs fail to hatch, then the mutant is scored as non-maternal (N). An M result indicates that expression of the + allele in the parent allows m/m zygotes to hatch and grow to adulthood. A result of N indicates the opposite: that the + allele must be expressed in the zygote for hatching to occur. Out of 23 zyg mutants tested, 3 were scored N and 20 were scored M in the A test. Therefore, for most of the genes defined by these mutants, expression in the parent is sufficient for zygote survival, even if the gene is not expressed in the zygote. B test: Homozygous (m/m) hermaphrodites reared at 25 C are mated with N2 (+/+) males. If eggs fail to hatch at 25 C, but mated hermaphrodites shifted to 16 C produce cross progeny to give proof of mating, then the mutant is scored M. If cross progeny appear in the 25 C mating, then the mutant is scored N. An M result indicates that expression of the + allele in the zygote is not sufficient to allow m/+ progeny of an m/m hermaphrodite to survive. Conversely an N result indicates either that zygotic expression of the + allele is sufficient for survival, or that a sperm function or factor needed for early embryogenesis can be supplied paternally (see C test below). Out of the 23 zyg mutants tested, 11 were scored M and 12 were scored N. The combined results of A and B tests and their simplest interpretation are as follows. Ten mutants are M,M; the genes defined by these mutants must be expressed in the hermaphrodite parent for the zygote to survive. Ten mutants are M,N; these genes can be expressed either in the parent or in the zygote. Two mutants are N,N; these genes must be expressed in the zygote. One mutant is N,M; this gene must be expressed both in the maternal parent and in the zygote. C test: Homozygous (m/m) hermaphrodites reared at 25 C are mated with heterozygous (m/+) males. If rescue by a +/+ male in the B test depends on the + allele, then only half the cross progeny zygotes of a C test mating (m/+ male x m/m hermaphrodite) should survive. However, if rescue depends on a function or cytoplasmic component from the male sperm, then all the cross progeny zygotes in a C test should survive. Of the 10 M,N mutants, 6 have been C tested; one exhibited paternal rescue independent of the + allele. The A and B tests also were carried out on 16 mutants that arrest before the L3 molt (acc mutants). In the A test on 2 of these mutants, all m/m progeny of m/+ parents grew to adulthood at 25 C. Therefore, parental contributions are sufficient to overcome a progeny mutational block as late as the L2 stage. All 16 acc mutants scored N in the B test.

Ali Khan L et al. (1994) Worm Breeder's Gazette "cej-1 Encodes a Novel Protein With Poly-Threonine Motif"

Siddiqui SS, Fukushige T, Ali Khan L, Tsukita Sh, Tabish M, Itoh M

[Worm Breeder's Gazette, 1994]

cej-1 Encodes a Novel Protein with Poly-Threonine Motif M. L. A. Khanl, M. Tabish, T. Fukushigel1 S. Tsukita2, M. Itoh , Sh. Tsukita , and S. S. Siddiqui. (1): Lab. of Molecular Biology, Dept of Ecological Engg. Toyohashi Univ. Technology, Toyohashi 441, and (2). National Institute for Physiological Sciences, Okazaki 444, Japan.

Zipkin ID et al. (1994) Worm Breeder's Gazette "Looking For M in All the Wrong Places."

Kenyon CJ, Zipkin ID

[Worm Breeder's Gazette, 1994]

Looking for M in all the Wrong Places Iian Zipkin and Cynthia Kenyon Department of Biochemistry University of California, San Francisco, CA 94143-0554 We are primarily interested in the genetic and molecular control of directed cell migration. Towards this end, we have been looking for mutants defective in the early embryonic long-range migration of the M mesoblast, which is born in the anterior of the embryo (near the future mid-pharynx) and migrates by the comma stage to just posterior to the gonad. Only one mutation to date has been published which affects the migration of M, that is unc-39(c~73, e257, rh72)V (Manser and Wood, 1990). To facilitate screening for additional M migration-defective mutants we decided to visualize M using a GFP (Green Fluorescent Protein, thanks to Marty Chalfie) reporter construct. This construct (muIS16; courtesy Craig Hunter) is driven by the mab-5 promoter and has been shown to be expressed in M until at least mid-Ll. It is hoped that screening for a fluorescent cell in the anterior of newly- hatched larvae will be a convenient way to isolate more M migration mutants. Preliminary screening (of only 600 F1 clones) has in fact identified one new mutant, which exhibits a very low penetrance M migration defect. As a test for the premise of this screen, we examined larvae of the genotype unc 39(ct73); mulS16 to see what a fluorescent M in the anterior would look like. Manser and Wood (1990) reported that M is in an abnormal location 61% of the time in ct73. By GFP visualization, we find that number to be slightly low; in our hands M is anteriorly misplaced in approximately 80% of all Lls seen. M can end up anywhere between the posterior pharynx and V3 when misplaced. In addition, we find that M exhibits an abnormal morphology in unc-39(ct73); muIS16. In wild-type, M is a fairly large cell with a regular, rectangular shape and smooth edges. In contrast, in unc-39(ct73); muIS16 M has a variable, irregular cell shape, with multiple, filopodia-like extensions often extending quite far both anteriorly and posteriorly. These extensions look almost axonal, and in general M appears "stretched out". See Figure 1 for a typical example. Sample pictures will also appear on the WWW site "http: To further investigate this phenomenon, we looked at several mutants by GFP and scored M's position and morphology. In the wild-type muIS16 background, M had a normal position and morphology in all but one of over 200 Lls scored. In unc- 39(ct73); muIS16, M had an abnormal morphology in over 90% of animals scored, whether it was in the correct position or not. M was also seen to have an abnormal morphology in 11/40 Lls of the genotype mab-5(e2088)III; muIS16 (mab-5 being the worm HOM gene related to Antennapedia), and in two of these cases M was anteriorly displaced. It is possible that there is some linked mutation in the muIS16 background which potentiates this morphology defect, however M is significantly affected in both mab-5 and unc-39. Finally, in the new mutant, M has a normal morphology even when anteriorly displaced, further demonstrating that these characteristics are genetically separable.

Wolf N et al. (1978) Worm Breeder's Gazette

Wolf N, Hirsh DI

[Worm Breeder's Gazette, 1978]

We have examined the early cleavages of our ts zyg mutants by Nomarski optics and measured the number of nuclei in the embryos as a function of time at restrictive temperature using Hoechst stain. We find that all of the strict maternal mutants (M,M) either have abnormal early cleavages or never progress beyond 200 nuclei or both. Two of the other zyg mutants display abnormal early cleavages. Interestingly these are the paternal mutant B235 (M,N,P) and the anomalous mutant B261 (M,N,?). None of the other mutants displays abnormal early cleavages or stops before 200 nuclei. The first cleavages can be schematically diagrammed as follows for N2 and for some of the mutants: [See Figure 1]

Ming Chih Tsai et al. (2002) Worm Breeder's Gazette "The C. elegans gastronome: differential palates for Mycobacterium smegmatis and Mycobacterium tuberculosis"

Scott Emmons, John Chan, Ming Chih Tsai, Jonathan Lipton

[Worm Breeder's Gazette, 2002]

It has been observed that certain strains of Pseudomonas aeroginosa , when served as the only food source, are lethal to the nematode worm Caenorhabiditis elegans . This observation has led to the use of C. elegans for the expeditious screening of virulence factors of P. aeroginosa , based on lethality. Importantly, this screen has allowed identification of P. aeuroginosa factors that proved essential for virulence in plant and mice. We have initiated studies to test the suitability of the use of C. elegans to screen for virulence factors in Mycobacterium tuberculosis . The relatively avirulent, rapid-growing M. smegmatis (MC 2 155) was initially used to examine the behavior of the nematode when offered mycobacteria as the sole food source. Preliminary studies revealed that C. elegans readily consumes M. smegmatis . Some worms, however, migrated away from the M. smagmatis lawn in the initial period following transfer to the center of the lawn, only to return later. This temporary avoidance was not observed on the Escherichia coli (OP50) lawn. Interestingly, though not quantified, enhanced sexual activities were observed in worms fed M. smegmatis as the sole diet, as assessed by the increased tendency of pairing of males and hermaphrodites. This apparent enhancement in sexual activities could be the result of aggregative behavior induced by mycobacterial noxious stimuli. The aversion displayed by C. elegans to M. smegmatis was confirmed in another set of experiments. In these studies, eggs derived from bleach-treated gravid worms, deposited on a bacteria-free region of an agar plate seeded with the organism of interest ( E. coli , M. smegmatis , or M. tuberculosis ), were allowed to hatch and the migration of young larvae to the bacterial lawn monitored. While virtually all hatched larvae migrated to the E. coli lawn within 24 h, those seeded next to the virulent M. tuberculosis lawn avoided the tubercle bacillus completely. Trafficking of the larvae to the relatively avirulent M. smegmatis was apparent, although a significant number of worms still failed to reach the MC 2 155 lawn at the end of 48h. Young larvae obtained by the method described above were also followed to evaluate the effects of different diets on overall C. elegans development and reproduction. On M. smegmatis plates, the ability of young larvae to develop and reproduce appeared to be comparable to those fed E. coli , although the number of eggs produced was not enumerated. In addition, as described above, C. elegans readily feeds on MC 2 155. By contrast, on M. tuberculosis plates, development was markedly stunted: the larvae remained small and moved sluggishly. This specific developmental pattern of M. tuberculosis -fed C. elegans is most likely due to the worm's aversion to the tubercle bacillus as a diet, and hence starvation. In summary, the degree of shunning of C. elegans from the relatively avirulent M. smegmatis and the virulent M. tuberculosis differs significantly, as assessed by migration toward the food source, consumption of the specific mycobacterial species, and development. It is also noteworthy that C . elegans mating activities are enhanced when M. smegmatis is offered as the sole food source. Thus, although the C. elegans virulence screen may not be an expeditious or a suitable system for the study of M. tuberculosis pathogenesis, the species-specific effects of mycobacteria on some behaviors of C. elegans as complex as sexual activities and food consumption, and on the developmental process may deserve further investigation.

Butler JA et al. (1994) Worm Breeder's Gazette "Looking For Extracellular Matrix Proteinases in C. elegans"

Kramer JM, Butler JA

[Worm Breeder's Gazette, 1994]

LOOKING FOR EXTRACELLULAR MATRIX PROTEINASES IN C. ELEGANS. James A. Butler and James M. Kramer, Northwestern University Medical School. Department of CMS Biology, Chicago IL 60611

Miller DM et al. (1992) Worm Breeder's Gazette "unc-4 LacZ Expression in A-Type Motor Neurons"

Miller DM, Niemeyer CJ

[Worm Breeder's Gazette, 1992]

unc-4 LacZ expression in A-type motor neurons David M. Miller and Charles J. Niemeyer, Dept. of Cell Biology, Duke Univ. Medical Ctr, Durham, NC 27710

Zetka M-C et al. (1993) Worm Breeder's Gazette "Mapping of the rec-1 Mutation"

Rose AM, Zetka M-C

[Worm Breeder's Gazette, 1993]

MAPPING OF THE rec-1 MUTATION Monique-Claire Zetka and Ann M. Rose, Dept. of Medical Genetics, 6174 University Blvd., University of British Columbia, Vancouver, B.C., V6T lZ3.

Baillie DL et al. (1977) Worm Breeder's Gazette "Lethal Mutations Generated at Different Dosages of EMS"

Moerman DG, Rose AM, Riekki KRC, Baillie DL

[Worm Breeder's Gazette, 1977]

The effect of E.M.S. dosage on the rate of sex linked lethal induction has been investigated at four different concentrations of E. M.S.; .0125 M, .025 M, .05 M, and .1M. A control, using no E.M.S. was run in parallel. Mutagenized dpy-5 worms were self crossed and the F1 subsequently mated to N-2 males so that the F2 sex ratio could be scored. The rate of x-linked lethal induction at .05 M was found to be 25%, in close agreement with previous experiments in our lab. A fractionation of broods into three 24 hour egg lays revealed that the highest frequency of x-linked lethals occurs at .05 M in brood three. Broods one and two appear to have a lower rate of induced lethals, which may be explained (at least in brood one) by the fact that the mutagenized parent contained fertilized eggs insensitive to E.M.S. treatment. Almost all F1 individuals in brood three (.05 M E.M.S.) carried a sex linked lethal. The x-linked lethal induction rate is seriously affected by the stage of gametogenesis, at the time of E.M.S. treatment. Double hit mutations modify the deceptively simple relationship between E.M.S. concentration and lethal induction rate, lowering it at higher concentrations. At .05 M E.M.S. (standard dosage), the number of lethal hits is high, and this should be taken into consideration when choosing a dosage for the generation of point mutations. This study has support by a grant from the National Research Council of Canada.

Kipreos ET et al. (1992) Worm Breeder's Gazette "Cloning of the C. elegans Tumor Suppressor Genes lin-19 and lin-23"

Hedgecock EM, Kipreos ET

[Worm Breeder's Gazette, 1992]

Cloning of the C. elegans tumor suppressor genes lin-l9 and lin-23. Edward T. Kipreos and Edward M. Hedgecock Department of Biology, Johns Hopkins University, Baltimore, MD 21218