La proteins from Xenopus laevis. cDNA cloning and developmental expression.
In mammalian nuclei, newly-synthesized RNA polymerase III transcripts are transiently associated with a phosphorylated polypeptide of approximately 50 kDa called the La protein. Here we provide evidence that the frog Xenopus laevis contains mRNAs for two highly related La proteins, each apparently encoded by a single gene. Both forms of the La protein contain the RNP-80 motif previously identified in many RNA binding proteins. The steady state levels of La mRNAs and protein are approximately constant in oocytes, eggs and embryos. This implies a progressive and severe decrease in these levels on a per cell basis during early development. In particular, neither the La mRNA nor protein level increases at the mid-blastula transition, the time when RNA polymerase III transcription first occurs during embryogenesis.
Scherly
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D
Département de Génétique et Microbiologie, Centre Médical Universitaire, Genève, Switzerland.
Stutz
F
F
Lin-Marq
N
N
Clarkson
S G
SG
D000595:Amino Acid Sequence; D000818:Animals; D001324:Autoantigens / Q000235:genetics* / Q000302:isolation & purification; D003001:Cloning, Molecular; D015870:Gene Expression; D015723:Gene Library; D008969:Molecular Sequence Data; D010443:Peptide Chain Termination, Translational; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D012261:Ribonucleoproteins / Q000235:genetics* / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics*; D000097585:SS-B Antigen
D001324:Autoantigens; D012333:RNA, Messenger; D012261:Ribonucleoproteins; D000097585:SS-B Antigen