Worm Breeder's Gazette 11(2): 89

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Suppression of mup-1 Alleles by dpy-10 and dpy-11

Thierry Bogaert and Phuay Yee Goh

Mup-1 (e2347) larvae hatch as curled up (kinked) dpy-ish worms with 
a smooth cuticle, a functional wild type pharynx and contracting body 
wall muscles with attachments across quadrants (WBG,10(3),104 and Worm 
Meeting 1989 abstract, 278).
Location of three additional mup-1 alleles: A weak allele with 70% 
penetrance, mup-1(e2430), was recovered in a screen for larval lethals 
identical to the one in which mup-1(e2347) was isolated (WBG,10(3),104)
.
Mup-1 (e2430)/nDf3 larvae are mup (mup-1 maps 4.4 m.u.  left of unc-
85 on II and is deleted in nDf3).  To obtain an amorphic mup-1 allele 
we did a precomplementation screen: N2 males and hermaphrodites were 
mutagenized with EMS and mated.  Individual F1 males were mated with 
two or three e2430/tra-2(q122gf) females on a small petri dish.  Tra-2(
q122gf) is a dominant feminizing mutation.  All F1 offspring therefore 
arise from outcrossing.  We screened 2300 plates for mup F1 and 
isolated 2 new mup-1 alleles, e2434 and e2436 (which also map left of 
unc-85 on chromosome II).
The four alleles form the following allelic series (from weak to 
strong): e2430, e2436, e2347 and e2434.  e2434 embryos are mups which 
die as L1.  A certain percentage of e2434 embryos die as threefold 
mups in the egg shell.
Suppression by dpy-10 and dpy-11.  The two new hypomorphic alleles 
of mup-1(e2436 and e2430) are suppressed by dpy-10(e128) and dpy-11(
e224) in a similar way as e2347 (see WBG, 10(3),104) while the 
stronger allele e2434 is not.  Hypomorphic alleles of glp-1 are 
similarly suppressed by dpy-10 and dpy-11, while putative null alleles 
are not (Maine and Kimble (1989), Development 105, 133-143).  Mup-1 
may thus also be involved in a cell-surface or extracellular matrix 
process and mup-1(e2434) may be a mup-1 null allele.  A putative null 
allele of dpy-10(m481) also suppresses mup-1(e2430) indicating that 
mup-1 does not interact directly with dpy-10.  A general disruption of 
the ECM may improve the functioning of a partially active mup-1 
product.
We thank Tim Schedl for suggesting the use of tra-2(q122gf) for 
complementing mutants and precomplementation screening.  We find it 
useful in a variety of crosses where offspring arising from selfing is 
undesirable.  We thank J.  Kramer for dpy-10(m481).