Meeting Abstract

P3.144  Tuesday, Jan. 6  Homebox gene characterization and expression in developing zooids of the marine bryozoan Membranipora membranacea TEMKIN, M.H.*; MISERCOLA, B.; SONAGERE, M.; DIXON, E.; St. Lawrence Univ; St. Lawrence Univ; St. Lawrence Univ; St. Lawrence Univ mtemkin@stlawu.edu

Bryozoans are a large group of colonial invertebrates that live in marine and freshwater habitats. New individuals, or zooids, of a bryozoan colony are added through a process of asexual budding. As each zooid forms, it develops specific structures along its anteroposterior axis. During animal development, regions of the body along the anteroposterior axis are specified through the biochemical environment established by transcription factors that are coded for by homeobox genes, including a subclass of homeobox genes called Hox genes. Initial steps in understanding how bryozoan zooids establish structures along their anteroposterior axis are to characterize their homeobox genes and to determine the expression of these genes during the differentiation of asexually budded individuals. Here we present data on the full protein coding sequences of four homeobox genes expressed during the development of zooids in colonies of the marine bryozoan Membranipora membranacea. These genes are the anterior Hox gene Deformed (Dfd), the central Hox gene Lox5, the posterior Hox gene Post-2, and the EHGBox gene Gbx2. Initial sequences for these genes were obtained by PCR using primers complimentary to conserved homeobox regions of genomic DNA. Using primers based on these conserved homeobox regions, the mRNA sequences of these genes were obtained by 3′ and 5′ RACE. RT-PCR was used to confirm that the sequences obtained from 3′ and 5′ RACE belonged to the same mRNA. Based on these mRNA sequences probes were synthesized for visualizing gene expression in developing zooids using in situ hybridization.