DExH-box helicase 29 (DHX29) is a 155 kDa protein that in humans is encoded by the DHX29 gene. [5]
DExH-box helicase 29 (DHX29) is a 155 kDa protein that in humans is encoded by the DHX29 gene. [5]
This gene encodes a member of the DEAH (Asp-Glu-Ala-His) subfamily of proteins, part of the DEAD (Asp-Glu-Ala-Asp) box family of RNA helicases. The encoded protein functions in translation initiation, and is specifically required for ribosomal scanning across stable mRNA secondary structures during initiation codon selection. [6] This protein may also play a role in sensing virally derived cytosolic nucleic acids. [7] Knockdown of this gene results in reduced protein translation and impaired proliferation of cancer cells. [8]
DHX29 has been shown to interact with the eukaryotic small ribosomal subunit (40S) and eIF3. [9] [10] [11] [12]
The preinitiation complex is a complex of approximately 100 proteins that is necessary for the transcription of protein-coding genes in eukaryotes and archaea. The preinitiation complex positions RNA polymerase II at gene transcription start sites, denatures the DNA, and positions the DNA in the RNA polymerase II active site for transcription.
Eukaryotic translation is the biological process by which transfer RNA is translated into proteins in eukaryotes. It consists of four phases: gene regulation, elongation, termination, and recycling.
The Kozak consensus sequence is a nucleic acid motif that functions as the protein translation initiation site in most eukaryotic mRNA transcripts. Regarded as the optimum sequence for initiating translation in eukaryotes, the sequence is an integral aspect of protein regulation and overall cellular health as well as having implications in human disease. It ensures that a protein is correctly translated from the genetic message, mediating ribosome assembly and translation initiation. A wrong start site can result in non-functional proteins. As it has become more studied, expansions of the nucleotide sequence, bases of importance, and notable exceptions have arisen. The sequence was named after the scientist who discovered it, Marilyn Kozak. Kozak discovered the sequence through a detailed analysis of DNA genomic sequences.
A release factor is a protein that allows for the termination of translation by recognizing the termination codon or stop codon in an mRNA sequence. They are named so because they release new peptides from the ribosome.
Eukaryotic initiation factors (eIFs) are proteins or protein complexes involved in the initiation phase of eukaryotic translation. These proteins help stabilize the formation of ribosomal preinitiation complexes around the start codon and are an important input for post-transcription gene regulation. Several initiation factors form a complex with the small 40S ribosomal subunit and Met-tRNAiMet called the 43S preinitiation complex. Additional factors of the eIF4F complex recruit the 43S PIC to the five-prime cap structure of the mRNA, from which the 43S particle scans 5'-->3' along the mRNA to reach an AUG start codon. Recognition of the start codon by the Met-tRNAiMet promotes gated phosphate and eIF1 release to form the 48S preinitiation complex, followed by large 60S ribosomal subunit recruitment to form the 80S ribosome. There exist many more eukaryotic initiation factors than prokaryotic initiation factors, reflecting the greater biological complexity of eukaryotic translation. There are at least twelve eukaryotic initiation factors, composed of many more polypeptides, and these are described below.
60S ribosomal protein L5 is a protein that in humans is encoded by the RPL5 gene.
ATP-dependent RNA helicase A is an enzyme that in humans is encoded by the DHX9 gene.
60S ribosomal protein L28 is a protein that in humans is encoded by the RPL28 gene.
Eukaryotic translation initiation factor 1A, X-chromosomal (eIF1A) is a protein that in humans is encoded by the EIF1AX gene. This gene encodes an essential eukaryotic translation initiation factor. The protein is a component of the 43S pre-initiation complex (PIC), which mediates the recruitment of the small 40S ribosomal subunit to the 5' cap of messenger RNAs.
Pre-mRNA-splicing factor ATP-dependent RNA helicase PRP16 is an enzyme that in humans is encoded by the DHX38 gene.
ATP-dependent RNA helicase DDX39 is an enzyme that in humans is encoded by the DDX39 gene.
Eukaryotic translation initiation factor 1 (eIF1) is a protein that in humans is encoded by the EIF1 gene. It is related to yeast SUI1.
Probable ATP-dependent RNA helicase DDX23 is an enzyme that in humans is encoded by the DDX23 gene.
Probable ATP-dependent RNA helicase DHX36 also known as DEAH box protein 36 (DHX36) or MLE-like protein 1 (MLEL1) or G4 resolvase 1 (G4R1) or RNA helicase associated with AU-rich elements (RHAU) is an enzyme that in humans is encoded by the DHX36 gene.
Putative pre-mRNA-splicing factor ATP-dependent RNA helicase DHX16 is an enzyme that in humans is encoded by the DHX16 gene.
Eukaryotic translation initiation factor 4 G (eIF4G) is a protein involved in eukaryotic translation initiation and is a component of the eIF4F cap-binding complex. Orthologs of eIF4G have been studied in multiple species, including humans, yeast, and wheat. However, eIF4G is exclusively found in domain Eukarya, and not in domains Bacteria or Archaea, which do not have capped mRNA. As such, eIF4G structure and function may vary between species, although the human eIF4G 1 has been the focus of extensive studies.
The eukaryotic initiation factor-4A (eIF4A) family consists of 3 closely related proteins EIF4A1, EIF4A2, and EIF4A3. These factors are required for the binding of mRNA to 40S ribosomal subunits. In addition these proteins are helicases that function to unwind double-stranded RNA.
Eukaryotic initiation factor 3 (eIF3) is a multiprotein complex that functions during the initiation phase of eukaryotic translation. It is essential for most forms of cap-dependent and cap-independent translation initiation. In humans, eIF3 consists of 13 nonidentical subunits (eIF3a-m) with a combined molecular weight of ~800 kDa, making it the largest translation initiation factor. The eIF3 complex is broadly conserved across eukaryotes, but the conservation of individual subunits varies across organisms. For instance, while most mammalian eIF3 complexes are composed of 13 subunits, budding yeast's eIF3 has only six subunits.
The 43S preinitiation complex is a ribonucleoprotein complex that exists during an early step of eukaryotic translation initiation. The 43S PIC contains the small ribosomal subunit (40S) bound by the initiation factors eIF1, eIF1A, eIF3, and the eIF2-Met-tRNAiMet-GTP ternary complex (eIF2-TC).
DExH-box helicase 34 is a protein that in humans is encoded by the DHX34 gene.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.
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