W. Gu et al., THE RNA-BINDING AND DNA-BINDING PROTEIN TB-RBP IS SPATIALLY AND DEVELOPMENTALLY-REGULATED DURING SPERMATOGENESIS, Molecular reproduction and development, 49(3), 1998, pp. 219-228
Testis brain RNA-binding protein (TB-RBP) suppresses translation in vi
tro and attaches mRNAs to microtubules by binding to conserved element
s in the 3' untranslated regions (UTRs) of specific testis and brain m
RNAs. Purification of TB-RBP from testicular and brain cytoplasmic ext
racts has revealed that mouse TB-RBP is 99% identical to the human pro
tein translin, a recombination ''hot spot'' binding protein associated
with chromosomal translocations. Using a cDNA encoding TB-RBP, the ge
ne copy number and the developmental expression of TB-RBP have been an
alyzed by Southern blotting, Northern blotting, and in situ hybridizat
ion. in the mouse, TB-RBP is encoded by a single copy gene. In mouse t
estes, three TB-RBP mRNAs of about 1.2, 1.7, and 3.0 kb are developmen
tally regulated with high levels of expression in meiotic and postmeio
tic germ cells. A fourth TB-RBP transcript of about 3.2 kb is seen in
the brain. In situ hybridization confirms high revels of testicular TB
-RBP mRNAs in meiotic and postmeiotic cells, with the highest levels o
f TB-RBP mRNAs in pachytene spermatocytes and round spermatids of the
mouse and in round spermatids of the rat. RNase H digestion assays rev
eal that the three TB-RBP mRNAs of mouse testes result from processing
differences in their 3' untranslated regions. These data demonstrate
that multiple TB-RBP mRNAs are primarily expressed in meiotic and post
meiotic germ cells in the mammalian testis, and although the specific
RNA-binding ability of TB-RBP appears limited to brain and testis, TB-
RBP mRNAs are widely expressed. (C) 1998 Wiley-Liss, Inc.