Worm Breeder's Gazette 14(1): 73 (October 1, 1995)

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

flr-4 is rescued

Masaya Take-uchi1,2, Minoru Kawakami2, Takeshi Ishihara2, Misako Urasaki2, Isao Katsura1,2

1 The Graduate University for Advanced Studies
2 National Institute of Genetics, Mishima, 411, Japan

We are interested in the functions and genetic interactions of the flr
genes, which are defined by fluoride-resistant mutations. They are grouped
into two classes by the phenotypes, i.e., class 1 mutants (flr-1, flr-3,
flr-4) show slow growth, small blood size and strong resistance to
fluoride ion, whereas class 2 mutants (flr-2, flr-5) show normal growth,
normal brood size and weak resistance to fluoride ion. Phenotypes of
double mutants between the class 1 and class 2 mutations reveal complex
and interesting epistasis: they are almost normal in growth and brood size
but strongly resistant to fluoride ion (I.Katsura et al. Genetics 136,
145-154 (1994)). The flr mutations also affect neural functions:
K.Iwasaki, D.W.C.Liu and J.H.Thomas reported that the class 1 mutants show
short defecation cycle periods (Dec-s) (wm95, p286), while we found that
some of the flr mutants are defective in chemotaxis (unpublished results)
and most of them show synthetic Dauer-constitutive phenotypes (wm95,

To elucidate the molecular mechanism of the functions and interactions of
the flr gene products, we cloned flr-1 and flr-3 by transposon tagging.
flr-1 encodes a degenerin-like ion channel, whereas flr-3 encodes a
protein kinase or a kinase-like molecule belonging to a new family (wm95,

Furthermore, we recently found that the cosmid F09B12 rescues the slow-
growing and Dec-s phenotypes, if it is injected into the gonad of the
flr-4(ut7) mutant. A major part of the cosmid has been sequenced already
by the genome project. Since it contains an ORF that shows homology to
KSS1 protein kinase, we are now testing if subclones containing this ORF
can rescue the flr-4 mutation. We expect the studies on the flr genes will
reveal a new signal transduction system that affects growth rate and some
neural functions in C. elegans.