RRC ID 31027
Author Nakamura M, Matsumoto K, Iwamoto Y, Muguruma T, Nakazawa N, Hatori R, Taniguchi K, Maeda R, Matsuno K.
Title Reduced cell number in the hindgut epithelium disrupts hindgut left-right asymmetry in a mutant of pebble, encoding a RhoGEF, in Drosophila embryos.
Journal Mech. Dev.
Abstract Animals often show left-right (LR) asymmetry in their body structures. In some vertebrates, the mechanisms underlying LR symmetry breaking and the subsequent signals responsible for LR asymmetric development are well understood. However, in invertebrates, the molecular bases of these processes are largely unknown. Therefore, we have been studying the genetic pathway of LR asymmetric development in Drosophila. The embryonic gut is the first organ that shows directional LR asymmetry during Drosophila development. We performed a genetic screen to identify mutations affecting LR asymmetric development of the embryonic gut. From this screen, we isolated pebble (pbl), which encodes a homolog of a mammalian RhoGEF, Ect2. The laterality of the hindgut was randomized in embryos homozygous for a null mutant of pbl. Pbl is a multi-functional protein required for cytokinesis and the epithelial-to-mesenchymal transition in Drosophila. Consistent with Pbl's role in cytokinesis, we found reduced numbers of cells in the hindgut epithelium in pbl homozygous embryos. The specific expression of pbl in the hindgut epithelium, but not in other tissues, rescued the LR defects and reduced cell number in embryonic pbl homozygotes. Embryos homozygous for string (stg), a mutant that reduces cell number through a different mechanism, also showed LR defects of the hindgut. However, the reduction in cell number in the pbl mutants was not accompanied by defects in the specification of hindgut epithelial tissues or their integrity. Based on these results, we speculate that the reduction in cell number may be one reason for the LR asymmetry defect of the pbl hindgut, although we cannot exclude contributions from other functions of Pbl, including regulation of the actin cytoskeleton through its RhoGEF activity.
Volume 130(2-3)
Pages 169-80
Published 2013-2
DOI 10.1016/j.mod.2012.09.007
PII S0925-4773(12)00092-5
PMID 23041176
MeSH Alleles Animals Body Patterning / genetics Cell Count Cell Polarity Cytokinesis Drosophila Proteins / genetics* Drosophila Proteins / metabolism Drosophila melanogaster / cytology Drosophila melanogaster / embryology* Drosophila melanogaster / genetics Epithelial Cells / physiology Epithelium / embryology Epithelium / metabolism Gastrointestinal Tract / cytology Gastrointestinal Tract / embryology* Gene Deletion Gene Expression Guanine Nucleotide Exchange Factors / genetics* Guanine Nucleotide Exchange Factors / metabolism Homozygote Organ Specificity Point Mutation RNA Splice Sites Sequence Analysis, DNA
IF 1.9
Times Cited 5