Worm Breeder's Gazette 16(5): 38 (February 1, 2001)

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.

Monoclonal Antibody MH33 Recognizes a Gut-specific Intermediate Filament

Tetsunari Fukushige, Jim McGhee

Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, CANADA

        The monoclonal antibody MH33 was produced by Francis and
Waterston (1985) and detects a structure beneath the microvilli of
intestinal cells, probably the terminal web.  At the comma stage of
embryogenesis, staining is both apical and cytoplasmic; apical staining
becomes predominant in later stages up to the adult.  The MH33 staining
pattern differs from that produced by MH27, which recognizes a component
of the adherens junction at the basolateral side of gut cells.  To
identify the MH33 antigen, we screened a C. elegans expression library
(kindly provided by Dr.  B. Barstead) by using  MH33 antibody (kindly
provided by Drs. Hresko and Waterson) and isolated 24 positive clone
from ~ 100,000 plaques screened.  A cross hybridization experiment
indicated that these positive clones all encoded the same product. 
Several of the largest inserts were sequenced and identified gene
F10C1.7, which encodes an intermediate filament.  Dodement et al.,
(1994) had previously identified this protein as intermediate filament
b2.  Two observations suggest that we have indeed cloned the correct
gene.  (1) Westerns could easily detect a ~60kD band in extracts from
twenty worms carrying a complete transgene; (Francis and Waterston
(1991) originally reported that MH33 identifies bands at 62 and 64 kD,
and Dodement et al. showed that alternative splicing gives rise to two
forms of b2 that differ in size by ~ 2kD). (2) A five kb fragment from
the F10C1.7 5!-flanking region, fused to pPD96.04, drives gut specific
expression, starting at comma stage and continuing in all later stages. 
The MH33-detected gut-specific intermediate filament gene should be
useful as a marker of early gut development (the gene is a potential
direct target of elt-2, for example, and contains the usual suspiciously
located WGATAR sites) and as a probe of intestinal cell structure, in
particular the generation of apical-basal polarity during gut