Dev Biol 1999 Jan 15;205(2):240-53
We have cloned a Caenorhabditis elegans homologue of the Drosophila gap
gene hunchback (hb) and have designated it hbl-1 (hunchback-like).
hbl-1 encodes a predicted 982-amino-acid protein, containing two putative
zinc-finger domains similar to those of Drosophila Hunchback. The
gene is transcribed embryonically, but unlike the maternally expressed
Drosophila hb, its mRNA is not detected in C. elegans oocytes. A
hbl-1::gfp reporter is expressed primarily in ectodermal cells during embryonic
and larval development. Double-stranded RNA-interference
(RNAi) was used to indicate hbl-1 loss-of-function phenotypes. Progeny
of hbl-1(RNAi) hermaphrodites exhibit a range of defects; the most
severely affected progeny arrest as partially elongated embryos or as hatching,
misshapen L1 larvae. Animals that survive to adulthood exhibit
variably dumpy (Dpy), uncoordinated (Unc), and egg-laying defective (Egl)
phenotypes, as well as defects in vulval morphology (Pvl). Abnormal
organization of hypodermal cells and expression of a hypodermal marker
in hbl-1(RNAi) animals suggests that most of the phenotypes observed
could be due to improper specification of hypodermal cells. The pattern
of hbl-1 expression is similar to that reported for the leech hunchback
homologue Lzf-2, suggesting that these proteins may have similar biological
functions in diverse species with cellular embryos. Copyright 1999
Academic Press.