Cold-Sensitive Mutants: Please Make Themselves Known!

Whilst browsing through the Forum Posts Archive for anything on cold-sensitive mutants (as well as looking simultaneously online) that might be useful as a rescue construct for strains grown @ 15 degrees, I came across this unanswered post:

Now, I don’t know whether no one had any suggestions at the time, or if the answer was so obvious that arparrish (and I) should already know the answer, but it got me wanting to find out more.

Armed with my third Latte of the day (I started early…), I did a bit of research and found mutations (before my hands started shaking uncontrolably) of two pharangeally-expressed genes (eat-6 & inx-6) that superficially appeared to be cold-sensitive.


inx-6 mentioned in a review: as being cold-sensitive, but in the paper cited;

it appears it is actually heat-sensitive! (or am I mistaken?).

Unfortunately, the eat-6(ad792) allele is not yet curated according to Wormbase, but does anyone out there have any further information on this allele? In the absence of any other possibility, this allele might be a useful starting point for us as we have a lot of daf mutants that sit happily at 15 degrees and don’t like 25 degrees at all.

More info on the eat-6(ad792) allele (but not eat-6 alleles generally as they seem not to follow the ad792 trend) or other cold-sensitive mutants would be most welcome.


I don’t know anything about these alleles (I just found them in a search just now), but I’ve got some candidates for you from Worm II. I’ve skipped some that were especially unlikely to be helpful.

The Baillie lethals in there, which might among seem the most promising alleles for your purpose, haven’t been cloned – but there are multiple alleles of all of them, so you could clone them in short order by sequencing.

deg-1 X − 1.32 u38
ts, dm; touch-insensitive and prod-insensitive only in tail; PVC interneurons degenerate at L1/L2, certain other neurons die at hatching (some IL1, also probably AVG) or L4 molt (probably AVD). ES2. OA1 (dominant): u529 (identical). Intragenic revertants (e.g., u38u175) are wt (probable null phenotype). Also recessive gf allele: u506 (cs embryonic-lethal, arrest at 2-fold with cell degenerations at 15°C; see also des-1,4) CLONED: encodes predicted membrane protein; two transmembrane domains surrounding Cys-rich domain; Deg alleles are A707V (u38, second transmembrane domain) and A393T (u506, predicted extracellular). [Chalfie and Wolinsky 1990; Hong and Driscoll 1994; Garcia-Anoveros et al. 1995] [MP, TU]

dif-1 IV 3.40 e2562
maternal-effect embryonic-lethal (mn); embryos arrest at the completion of gastrulation with little or no tissue differentiation; probable null. OA4: e2577 (similar), e2591cs (100% dead eggs at 15°C, variably viable and sometimes dumpy at 25°C; TSP 5−8 hours embryo), etc. CLONED: 1.2-kb transcript, present at all stages; encodes predicted 312-aa protein with similarity to mitochondrial carrier proteins. [Ahringer 1995]

egl-19 IV 3.38 n582
sd; moderate bloating; stimulated by imipramine, not by serotonin; slow and floppy; long; n582/Df more severe phenotypes. ES3 (adult) ES2 (other stages) ME1. NA(lf)>10: st556 (pka pat-5 ), st576, st577 (all embryonic-lethal, severe Pat, probable null phenotype). Also apparent gf alleles: ad695sd (pka eat-12 , weak Eat: terminal bulb stays contracted for longer than normal, sometimes >1 sec; corpus action normal; muscle hyperactivated, sticky pumping, short,ad695/+ similar but weaker phenotypes), n2368 (Eat: delayed relaxation and repolarization of terminal bulb; Egl: eggs of <10 nuclei are laid, vulval muscles show spontaneous contraction; Dpy: may be due to body muscles hypercontraction; Mab: protruding spicules. n2368/+ has a phenotype similar to but weaker than n2368. ES3 ME0. n2368 but not n2368/+has a cs Pat phenotype, penetrant at 12°C. ME0. Intragenic revertants, e.g., n2368ad979 are recessive Pat) CLONED: may encode calcium channel subunit. [Avery 1993a; Williams and Waterston 1994] [DA, MT]

kra-1 V 0.51 kh30
semidominant convulsive behavior in 30 mM ketamine or other NMDA antagonists; recessive cs Unc; variable motility; weakly resistant to cholinergic agonists, ouabain; normal muscle morphology. [HK]

let-327 V − 16.00 s247
cs larval-lethal; slow developer, translucent adult. OA3: s1485, s1496 (morphological abnormalities, lethal 25°C), s1799.[Johnsen and Baillie 1991] [BC]

let-331 V − 2.80 s427
cs mid larval-lethal or sterile adult. OA1: s1608 (slow development, sterile). [Johnsen and Baillie 1991] [BC]

let-339 V 0.56 s1444
early larval-lethal. OA2: s1019 (cs Mel), s1469 (variable, embryonic- to mid larval-lethal). [Johnsen and Baillie 1991] [BC]

let-343 V 0.56 s1025
embryonic-lethal. OA5: s816, s1410, s1428, s1579, s1465 (cs, slow development). [Johnsen and Baillie 1991] [BC]

let-349 V N s217
early larval-lethal. OA3: s502gri, s572 (cs, late larval-lethal), s1965uvi. [Johnsen and Baillie 1991] [BC]

lin-45 IV 3.27 sy96
subviable, >90% die as rod-like L1, escapers mostly Egl, Vul; suppresses lin-15 Muv; impenetrant P12 to P11transformation; partial maternal rescue of larval lethality; effects on male development resemble F and U ablation. OA1:n2018cs (most animals Vul or inviable at 15°C, 25% non-Vul at 25°C). CLONED: pka raf-1 ; encodes 813-aa predicted protein with extensive similarity to raf kinases; dominant-negative transgene frequently Vul. [Han et al. 1993] [MH, MT, PS]

mec-2 X − 4.61 u8
amb; touch-insensitive; lethargic. ES2. OA>50: e75 (pka che-9 ; recessive, ME3), u7cs, e1084 (probable null), e1514, e1608dm, u284sd, etc. Alleles vary in phenotype from weak recessive to strong dominant Mec; complex complementation. cloned: encodes predicted 440-aa protein with central similarity to human stomatin (65% identity over 247 aa); mec-2:lacZ expressed in cell bodies and processes of touch cells, some other neurons. [Chalfie and Au 1989; Huang et al. 1995]

sup-5 III − 0.11 e1464
sd; amber suppressor, partially or completely suppresses amber alleles of >40 different genes; slow-growing cs (sterile at 15°C), otherwise no phenotype alone; alteration in tRNATrp anticodon. ES3 (in presence of unc-13[e450], etc.) ME1. OA>20: all identical to e1464, e.g., e1877dm (pka sup-4 , dominant suppressor of unc-51 [e369amb]). Corresponds tortw-1 , tRNATrp structural gene. [Waterston and Brenner 1978; Wills et al. 1983]

unc-124 X − 2 hs10
cs; uncoordinated at 11°C, kinker; wt at 23°C; phenotype reversible within hours of temperature shift, throughout development; dominant interaction with some unc-7 alleles. NA1. [Hecht et al. 1996] [HH]

unc-125 X − 15 hs11
cs, dm; uncoordinated (coiled, kinked, slow) at 11°C, wt at 23°C; phenotype reversible within minutes of temperature shift, throughout development; hs11/+ similar. NA1. [Hecht et al. 1996] [HH]

unc-126 III − 0.4 hs12
cs; severely paralyzed at 11°C, wt at 23°C; tsP early. NA1. [Hecht et al. 1996] [HH]

unc-127 V 0.1 hs13
cs; uncoordinated coiler at 11C, wt at 23°C; TSP early. NA1. [Hecht et al. 1996] [HH]

thanks for the list and comments…yep I should have looked there as well. Indeed the Baillie lethals, let- series look good, but actually only one has a very clear cold-sensitive phenotype. As you said, they haven’t been cloned but I have the mutant down to +/- 8 map units on chromosome 5 and there’s a strain carrying the mutation and a balanced translocation so I’ll see if I can pull it out.