1. Abstract In developing male germ cells, newly synthesized protamine mRNAs are stored for up to 7 days before translational activation. Translational repression of protamine 1 (Prm1) mRNA requires sequences present in its 3' ... In developing male germ cells, newly synthesized protamine mRNAs are stored for up to 7 days before translational activation. Translational repression of protamine 1 (Prm1) mRNA requires sequences present in its 3' untranslated region (UTR) and substantial evidence suggests a role for the murine Y-box protein MSY4 in this process. To determine if MSY4 can mediate translational repression in vivo, we generated transgenic mice in which the temporal window of MSY4 expression was extended during spermatogenesis. Expression of MSY4 disrupted the normal completion of spermatogenesis and caused dominant sterility. Immunocytochemical analysis of several markers, including the protamines, indicated that MSY4 prevented normal activation of translation. mRNAs whose translation was inhibited contained at least one MSY4 RNA recognition site, suggesting sequence-dependent translational repression. Altered translational activation resulted in defective processing of protamine 2 and severe defects in sperm morphogenesis. These results suggest that MSY4 plays an active role in translational repression of several mRNAs in differentiating spermatids.
PMID: [12117816]
2. Abstract Y-box binding proteins, a large family of proteins, are involved in a variety of functions. The present study describes the expression of YB2, a rat Y-box binding protein, and/or RYB-a, an alternatively ... Y-box binding proteins, a large family of proteins, are involved in a variety of functions. The present study describes the expression of YB2, a rat Y-box binding protein, and/or RYB-a, an alternatively spliced product of the YB2 gene during spermatogenesis. YB2/RYB-a is thought to be the rat orthologue of mouse Y-box protein 3 (MSY3). An antibody which recognizes YB2/RYB-a was developed and applied in an immunochemical study of rat and mouse testes. We also carried out an in-situ hybridization study and Northern blot analysis of YB2/RYB-a and protamine 2 mRNA expression. Both YB2/RYB-a mRNA and the proteins appeared in prepubertal mouse testes, prior to the expression of the mouse protamine 2 mRNA. The mRNA and protein were present at high levels in spermatocytes, decreased in round to elongated spermatids, and were absent in spermatozoa. Since the protamine 2 mRNA was present at high levels in round and elongating spermatids, the proposed function of the YB2/RYB-a protein as a translational repressor of the mRNA was supported in mouse. The level and localization of YB2/RYB-a mRNA and protein expression in the rat testis was comparable to that in mouse testis, although rat testis is known to express a very low level of protamine 2, but is also likely to affect the expression of other proteins (including protamine 1) during spermatogenesis.
PMID: [11675468]
F. Giorgini, H. G. Davies and R. E. Braun (2002) Translational repression by MSY4 inhibits spermatid differentiation in mice. Development 129(15): 3669-79. PMID: [12117816]
F. Giorgini, H. G. Davies and R. E. Braun (2002) Translational repression by MSY4 inhibits spermatid differentiation in mice. Development 129(15): 3669-79. PMID: [12117816]
F. Giorgini, H. G. Davies and R. E. Braun (2002) Translational repression by MSY4 inhibits spermatid differentiation in mice. Development 129(15): 3669-79. PMID: [12117816]
F. Giorgini, H. G. Davies and R. E. Braun (2002) Translational repression by MSY4 inhibits spermatid differentiation in mice. Development 129(15): 3669-79. PMID: [12117816]
F. Giorgini, H. G. Davies and R. E. Braun (2002) Translational repression by MSY4 inhibits spermatid differentiation in mice. Development 129(15): 3669-79. PMID: [12117816]