Proteins homologous to the Xenopus germ cell-specific RNA-binding proteins p54/p56 are temporally expressed in mouse male germ cells.
Antibodies specific for the Xenopus oocyte cytoplasmic 6S mRNA-binding particle p54/p56 and antibodies against Xenopus germ cell DNA-binding protein FRG Y2 recognize two RNA-binding proteins of the mouse testis. The mouse testis proteins, estimated by SDS-PAGE to be about 48 and 52 kDa, form RNA-protein complexes with either translationally regulated or control RNAs, suggesting that they are sequence-independent RNA-binding proteins. The binding of the 48/52-kDa proteins to RNA is reduced by heparin. The expression of the 48/52-kDa mouse proteins is germ cell-specific and developmentally regulated in the testis with a maximal amount of the two proteins being detected in early postmeiotic cells (round spermatids), a cell type where many mRNAs are stored. The 48/52-kDa proteins are detected solely in the nonpolysomal fractions of postmitochondrial adult testis extracts and are not detected in extracts of brain, liver, or prepuberal testes from 12-day-old mice. We conclude that two RNA-binding proteins that appear to be immunological and functional homologues of the Xenopus germ cell-specific RNA/DNA-binding proteins p54/p56/FRG Y2 are present in male germ cells and form complexes with stored mRNAs.
Kwon
Y K
YK
Department of Biology, Tufts University, Medford, Massachusetts 02155.
Murray
M T
MT
Hecht
N B
NB
D000818:Animals; D001667:Binding, Competitive; D005786:Gene Expression Regulation; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008970:Molecular Weight; D010063:Ovum / Q000378:metabolism; D011479:Protamines / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D013087:Spermatids / Q000378:metabolism*; D013737:Testis / Q000378:metabolism*; D014981:Xenopus
D011479:Protamines; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C068621:protamine 2