High impact information on pbl

• Using various muscle differentiation markers, we found that Even skipped (EVE) expression in the dorsal mesoderm is greatly reduced in pbl mutant embryos [1].
• This idea is supported by allele-specific differences in the expressivity of the cytokinesis and cell migration phenotypes of different pbl mutants [2].
• Further analysis revealed that this phenotype is likely to be a consequence of an earlier defect. pbl mutant mesodermal cells fail to undergo the normal epithelial-mesenchymal transition (EMT) and dorsal migration that follows ventral furrow formation [1].
• Expression of a constitutively active form of HTL is unable to rescue the early cellular defects in pbl mutants, suggesting that PBL is required for the ability of HTL to trigger these cell shape changes [2].
• Strong genetic interactions were observed between citron and pbl alleles and constructs [3].

Biological context of pbl

• This phenotype is not a secondary consequence of failed cytokinesis, as it is rescued by a mutant form of pbl that does not rescue the cytokinetic defect [1].
• Here, we report the expression pattern of pbl during embryonic development [4].
• Mutations in pbl result in the absence of a contractile ring leading to a failure of cytokinesis and formation of polyploid multinucleate cells [4].
• In addition, levels of PBL protein cycle during each round of cell division with the highest levels of PBL found in telophase and interphase nuclei [4].
• We show that PEBBLE RNA and PBL protein have a similar tissue distribution and are expressed in a highly dynamic pattern throughout embryogenesis [4].

Anatomical context of pbl

• In a genetic screen we identified pebble (pbl) as a novel gene required for mesoderm migration. pbl encodes a guanyl nucleotide exchange factor (GEF) for RHO1 and is known as an essential regulator of cytokinesis [2].
• Our expression data correlate well with the phenotypes observed in pole cells and, particularly, with the absence of cytokinesis after cellular blastoderm formation in pbl mutants [4].

Other interactions of pbl

• Here we focus on the role of the pebble (pbl) gene of Drosophila melanogaster, a RhoGEF that is required for cytokinesis [5].

References