Meeting Abstract
How centralized nervous systems (CNSs) evolved remains an unresolved question. Previous studies in vertebrates and arthropods have revealed that similar neurogenic homologs regulate their CNS development. Such genes regulate important cellular processes like cell proliferation and differentiation. Here, we have isolated and studied the spatio-temporal expression patterns of neurogenic homologs in the annelid Capitella teleta, which belongs to a separate bilaterian clade (Spiralia) as compared to arthropods (Ecdysozoa) and vertebrates (Deuterosomia). This will help identify which aspects of bilaterian neurogenesis may have been ancestral or were derived within Spiralia. During C. teleta brain neurogenesis, neural precursor cells (NPCs) in the surface ectoderm proliferate and generate daughter cells that begin to exit the cell cycle, ingress inward, and generate neural subtypes. Using whole mount in-situ hybridization, Ct-soxB1 was detected in surface cells in the neuroectoderm whereas Ct-soxB was detected in overlapping domains of Ct-soxB1 expression, which indicates a possible interaction between the two classes of soxB factors similar to vertebrates. Ct-msi is expressed in a similar pattern as Ct-notch and Ct-delta, which might indicate involvement with the Notch pathway. Ct-pros expression suggests a possible role in specification of neural fate in early development of C. teleta. Ct-ngn is expressed in superficial cells, similar to Ct-ash1 and Ct-soxB1, whereas, Ct-neuroD is expressed in more internalized cells. Functional studies will help understand the role of these homologs during C. teleta neurogenesis.
