Related Experiment Video
Updated: Jul 27, 2026
10:24
Xenopus laevis as a Model to Identify Translation Impairment
Published on: September 27, 2015
Functional analysis of seven genes encoding eight translation initiation factor 4E (eIF4E) isoforms in Drosophila
Greco Hernández1, Michael Altmann, José Manuel Sierra
1Max-Planck-Institut für biophysikalische Chemie, Abt. Molekulare Biologie, Am Fassberg 11, Göttingen 37077, Germany. hgreco@gwdg.de
Mechanisms of Development
|April 5, 2005
Summary
Drosophila has eight eukaryotic initiation factor 4E (eIF4E) isoforms, with eIF4E-1 being crucial for embryonic cap-binding and development. Its overexpression causes dose-dependent defects, highlighting its essential role.
Area of Science:
- Molecular Biology
- Genetics
- Developmental Biology
Background:
- The Drosophila genome encodes eight eukaryotic initiation factor 4E (eIF4E) isoforms.
- Four isoforms (eIF4E-1, -2, -3, -4, -5) share structural similarities and are genomically clustered.
- All isoforms bind the mRNA cap structure (m7GpppN).
Purpose of the Study:
- To characterize the functions and expression patterns of Drosophila eIF4E isoforms.
- To determine the specific roles of eIF4E isoforms in embryonic development.
- To investigate the consequences of eIF4E-1 overexpression.
Main Methods:
- Genome sequencing analysis to identify eIF4E genes.
- In vivo functional assays using yeast mutants.
- Expression analysis via mRNA detection.
- Proteomic analysis of the eIF4F complex.
- Transgenic expression and phenotypic analysis in Drosophila.
Main Results:
- Most eIF4E isoforms interact with eIF4G or 4E-BP, except eIF4E-6 and -8.
- eIF4E-1, -2, -3, -4, and -7 can rescue yeast eIF4E-deficient mutants.
- eIF4E-1 mRNA is highly expressed in embryos; other isoforms are larval-specific.
- eIF4E-1 is essential for embryonic cap-binding and development, confirmed by mutant rescue and proteomic data.
- Overexpression of eIF4E-1 causes dose-dependent developmental defects.
Conclusions:
- eIF4E-1 is the primary isoform responsible for cap-binding during Drosophila embryogenesis.
- Differential expression of eIF4E isoforms suggests specialized roles throughout development.
- eIF4E-1 plays a critical, dose-sensitive role in regulating Drosophila development.
Related Concept Videos
02:33Initiation of Translation
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
02:28Leaky Scanning
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
02:24Ribosome Profiling
Ribosome profiling or ribo-sequencing is a deep sequencing technique that produces a snapshot of active translation in a cell. It selectively sequences the mRNAs protected by ribosomes to get an insight into a cell’s translation landscape at any given point in time.
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique helps...
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique helps...
01:30General Transcription Factors
Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of hemoglobin, is present in all cells of the body. However, it is only expressed in red blood cells because the transcription factors that can bind to the promoter sequences of the beta globin gene are only expressed in these cells. Tissue-specific transcription factors also ensure that mutations in these factors may impair only the function of...