Maternal effect lethal mutation. High incidence of males in surviving offspring. Not rescued by male mating. Temperature sensitive.

Heterozygotes are wild-type and segregate wild-type heterozygotes, DpyUncs (mnC1 homozygotes), and him-14 homozygotes that produce >95% dead embryos and 45% males. Among these surviving progeny, cytologically they have 12 univalents in diakinesis-stage oocytes owing to a failure to form crossovers during meiosis.

Bacteria. E. coli HT115(DE3) bacterial strain carrying pGC8. pGC8 is a partial cDNA of him-14 (ZK1127.11) cloned into the Timmons and Fire "double T-7 vector" L4440. The source of the cDNA is Yuji Kohara's clone yk240h12. pGC8 was constructed by inserting the 1.65kb KpnI/SacI fragment of the him-14 cDNA (from base pair 1071 to 192 base pairs beyond the stop codon) into the same sites in L4440. HT115(DE3) carrying pGC8 should be selected in the presence of 50 um/ml tetracyline and 100 um/ml ampicillin. Prior to an actual feeding experiment, it can be grown in liquid in the presence of amp alone (no tet) and then seeded onto NGM plates containing amp and 1 mM IPTG. This technique does not work well if the cells are old; therefore, the strain should be seeded onto IPTG-containing plates from a fresh overnight that was grown from a colony on an amp/tet plate. Biosafety Level: BSL-1. For more info see http://www.wormbook.org/wli/wbg17.1p32/

Heterozygotes are WT and segregate WT, DpyUncs and dead eggs. The nos-2(ok230) allele is due to deletion of bases 30999 to 33076 of cosmid ZK1127 (GenBank accession U58758) and also deletes a portion of the him-14 gene (him-14 is in an intron of nos-2).