Germ cell-specific proteins interact with the 3' untranslated regions of Prm-1 and Prm-2 mRNA
Date
1994-12Author
Braun, Robert E.
Lee, Keesook
Fajardo, Mark A.
Butner, Karen A.
Metadata
Show full item recordAbstract
The testis-specific mouse protamine genes (Prm-1 and Prm-2) are
transcribed in haploid round spermatids, their mRNAs stored as cytoplasmic
ribonucleoprotein particles and translated about 1 week later in
elongating spermatids. We have compared the in vitro translational
efficiencies of deproteinized Prm-1 mRNA isolated from purified
populations of germ cells and found that Prm-1 mRNA from round spermatids
translates as efficiently as Prm-1 mRNA from elongating spermatids,
suggesting that translation of Prm-1 mRNA is normally repressed in round
spermatids. Previous studies in transgenic mice have shown that the 3' UTR
of Prm-1 mRNA is necessary and sufficient for its translational control
(Braun et al., 1989). In this manuscript, we have used an RNA band shift
assay to identify an activity, present in cytoplasmic fractions of meiotic
spermatocytes and postmeiotic round spermatids, that binds the 3'UTRs of
both Prm-1 and Prm-2 mRNA. We have used 3' UTR deletion variants to map
the binding site to a 22-nt region within the Prm-1 3' UTR and to a 20-nt
region within the Prm-2 3' UTR. uv cross-linking of the RNA band shift
activities detected with the Prm-1 and Prm-2 3' UTRs generated the same
two RNA/protein complexes of 53 and 55 kDa. The presence of the binding
activity in the cell type and subcellular compartment associated with
Prm-1 and Prm-2 mRNA storage suggest that the activity may be actively
engaged in translational repression of these mRNAs.