Abstract
Purpose::
To determine the temporal and spatial expression of the mouse myo3B protein, an unconventional class III myosin, in the retina of animals of various ages. Class III myosins are characterized by a kinase domain at their N-terminus, and are expressed in an array of invertebrate and vertebrate organisms such as L. polyphemus, D. melanogaster, M. musculus, and H. sapiens. Thus far two different genes encoding class III myosins have been cloned from vertebrates, including mouse: myo3A which encodes a longer gene product, and myo3B which encodes a shorter gene product and is the focus of this study.
Methods::
An antibody raised against the tail of mouse myosin3B was used for the detection of the protein in the mouse retina. Western blots were performed using mouse retinal homogenates of various ages (P0-Adult) to investigate the expression of the protein throughout development. Immunocytochemistry (ICC) using frozen sections fixed in Cytoskel or 4% paraformaldehyde was used to explore the localization of the protein in the mouse retina.
Results::
Western blots demonstrated a 120 kDa protein that was specifically detected by the antibody and successfully removed after absorption against the antigen. This band was present in all ages tested (P0 to adult animals). ICC with adult mouse retinas using the same antibody revealed staining of the inner segments (IS) of the photoreceptors, some gangion cells (GC), and the outer plexiform layer (OPL).
Conclusions::
The mouse myosin3B protein is expressed in the mouse retina as early as P0 (postnatal day 0) and its expression is maintained through adulthood. These results correlate with previous Real-Time PCR data produced in our laboratory (J. Dalal, personal communication). This protein is mainly expressed in the inner segments of photoreceptors and ganglion cells of the P21 and adult retina.
Keywords: retina • development • immunohistochemistry