scholarly journals Sequence-Independent Assembly of Spermatid mRNAs into Messenger Ribonucleoprotein Particles

1999 ◽  
Vol 19 (5) ◽  
pp. 3904-3915 ◽  
Author(s):  
Edward E. Schmidt ◽  
Eric S. Hanson ◽  
Mario R. Capecchi
Keyword(s):  
Translational Control ◽  
Transcriptional Activity ◽  
Sperm Maturation ◽  
Mrna Sequence ◽  
High Transcriptional Activity ◽  
Ribonucleoprotein Particles ◽  
Messenger Ribonucleoprotein ◽  
Specific Mrnas ◽  
Sequence Requirements

ABSTRACT During mammalian spermatogenesis, meiosis is followed by a brief period of high transcriptional activity. At this time a large amount of mRNA is stored as messenger ribonucleoprotein (mRNP) particles. All subsequent processes of sperm maturation occur in the complete absence of transcription, primarily using proteins which are newly synthesized from these stored mRNAs. By expressing transgene mRNAs in the early haploid spermatids of mice, we have investigated the sequence requirements for determining whether specific mRNAs in these cells will be stored as mRNP particles or be assembled into polysomes. The results suggest that mRNAs which are transcribed in spermatids are assembled into mRNP particles by a mechanism that acts independently of mRNA sequence. Our findings reveal a fundamental similarity between the mechanisms of translational control used in spermatogenesis and oogenesis.

scholarly journals Translational Control of the Oogenic Program by Components of OMA Ribonucleoprotein Particles inCaenorhabditis elegans

Genetics ◽  
2014 ◽  
Vol 198 (4) ◽  
pp. 1513-1533 ◽  
Author(s):  
Caroline A. Spike ◽  
Donna Coetzee ◽  
Yuichi Nishi ◽  
Tugba Guven-Ozkan ◽  
Marieke Oldenbroek ◽  
...  
Keyword(s):  
Translational Control ◽  
Ribonucleoprotein Particles

scholarly journals A Retrospective on eIF2A—and Not the Alpha Subunit of eIF2

2020 ◽  
Vol 21 (6) ◽  
pp. 2054
Author(s):  
Anton A. Komar ◽  
William C. Merrick
Keyword(s):  
Translational Control ◽  
Ribosomal Subunit ◽  
Initiation Factor ◽  
Single Chain ◽  
Initiation Factors ◽  
Eif2α Phosphorylation ◽  
Specific Mrnas ◽  
Internal Initiation ◽  
And Function ◽  
Polypeptide Chains

Initiation of protein synthesis in eukaryotes is a complex process requiring more than 12 different initiation factors, comprising over 30 polypeptide chains. The functions of many of these factors have been established in great detail; however, the precise role of some of them and their mechanism of action is still not well understood. Eukaryotic initiation factor 2A (eIF2A) is a single chain 65 kDa protein that was initially believed to serve as the functional homologue of prokaryotic IF2, since eIF2A and IF2 catalyze biochemically similar reactions, i.e., they stimulate initiator Met-tRNAi binding to the small ribosomal subunit. However, subsequent identification of a heterotrimeric 126 kDa factor, eIF2 (α,β,γ) showed that this factor, and not eIF2A, was primarily responsible for the binding of Met-tRNAi to 40S subunit in eukaryotes. It was found however, that eIF2A can promote recruitment of Met-tRNAi to 40S/mRNA complexes under conditions of inhibition of eIF2 activity (eIF2α-phosphorylation), or its absence. eIF2A does not function in major steps in the initiation process, but is suggested to act at some minor/alternative initiation events such as re-initiation, internal initiation, or non-AUG initiation, important for translational control of specific mRNAs. This review summarizes our current understanding of the eIF2A structure and function.

scholarly journals The Major Core Protein of Messenger Ribonucleoprotein Particles (p50) Promotes Initiation of Protein Biosynthesisin Vitro

1998 ◽  
Vol 273 (6) ◽  
pp. 3574-3581 ◽  
Author(s):  
Valentina M. Evdokimova ◽  
Elizaveta A. Kovrigina ◽  
Dmitry V. Nashchekin ◽  
Elena K. Davydova ◽  
John W. B. Hershey ◽  
...  
Keyword(s):  
Core Protein ◽  
Ribonucleoprotein Particles ◽  
Messenger Ribonucleoprotein ◽  
Major Core Protein
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