ABSTRACT
The earthworm Perionyx excavatus is a species highly capable of bidirectional regeneration. Pair-rule genes are thought to have an ancestral function in arthropod segmentation. However, orthologs in annelids (i.e. Capitella teleta) do not exhibit segmental expression in the ectoderm or mesoderm. Their role in regeneration is currently unclear. Here, we report the expression profile of primary pair-rule genes (Pex-EvxA, Pex-EvxB, Pex-RuntA, Pex-RuntB, Pex-Hes1A, Pex-Hes1B, Pex-Hes4A, and Pex-Hey) found in P. excavatus using semi-quantitative reverse transcription-polymerase chain reaction. Our results indicated these genes showed variable expression during bidirectional regeneration. Six of these genes might play diverse and potentially critical roles in head and/or tail regeneration.
Subject(s)
Body Patterning/genetics , Oligochaeta/genetics , Regeneration/genetics , Amino Acid Sequence/genetics , Animals , Conservation of Natural Resources , Ectoderm/growth & development , Gene Expression Regulation, Developmental/genetics , Oligochaeta/growth & developmentABSTRACT
Genes of the twist family encode bHLH transcription factors known to be involved in the regulation and differentiation of early mesoderm. Here, we report our characterization of Hau-twist, a twist homolog from the leech Helobdella austinensis, a tractable lophotrochozoan representative. Hau-twist was expressed in segmental founder cells of the mesodermal lineage, in subsets of cells within the mesodermal lineage of the germinal plate, in circumferential muscle fibers of a provisional integument during segmentation and organogenesis stages and on the ventral side of the developing proboscis. Thus, consistent with other systems, our results suggest that twist gene of the leech Helobdella might function in mesoderm differentiation.
