Meeting Abstract
P2.97 Wednesday, Jan. 5 Characterization of Giant Danio and Rainbow Trout Primary Myoblast Culture Systems FROEHLICH, J.M.*; BIGA, P.R.; North Dakota State University; North Dakota State University jacob.froehlich@ndsu.edu
Investigations of zebrafish (Danio rerio) growth and development have revealed much about teleost muscle biology. However, this species exhibits more of a determinate growth pattern while most fish, including rainbow trout (Oncorhynchus mykiss) and giant danio (Danio aequipinnatus), exhibit indeterminate growth. In an effort to identify novel pathways utilized by indeterminate teleost satellite cells, we characterized primary myoblast culture systems obtained from giant danio and rainbow trout. Using cross-reactive antibodies generated for satellite cell specific markers (Pax7, Pax3, syndecan-4, and c-Met) and myogenic regulatory factors (MyoD, Myf5, and myogenin), we demonstrate the satellite cell nature of myogenic precursors extracted from giant danio. In rainbow trout, Pax7 immunostaining is not present. MyoD appears to be expressed throughout the myogenic program in both species, while myogenin seems to be restricted to giant danio myoblasts and is undetectable in rainbow trout, possibly as a consequence of antibody specificity. Myf5 is expressed very early during culture in giant danio while it is markedly absent in rainbow trout. Syndecan-4 and c-Met display similar patterns of expression in both species. Interestingly, Pax7 expression appears to be up-regulated in the later stages of myotube development in giant danio, coinciding with an increase in proliferation. This phenomenon may be due to the antiapoptotic effects of Pax7 as cells reach confluence. Rainbow trout display a similar increase in proliferation. Pax3 expression in advanced myoblasts and myotubes and the lack of widespread myogenin expression may suggest a novel mechanism specific to indeterminate growth. This description further validates these two organisms as models for studying mechanisms of post-larval hyperplasia.
