Poor cerebral inflammatory response in eIF2B knock-in mice: implications for the aetiology of vanishing white matter disease.

Background: Mutations in any of the five subunits of eukaryotic translation initiation factor 2B (eIF2B) can lead to an inherited chronic-progressive fatal brain disease of unknown aetiology termed leucoencephalopathy with vanishing white matter (VWM). VWM is one of the most prevalent childhood white matter disorders, which markedly deteriorates after inflammation or exposure to other stressors. eIF2B is a major housekeeping complex that governs the rate of global protein synthesis under normal and stress conditions.

A point mutation in translation initiation factor eIF2B leads to function--and time-specific changes in brain gene expression.

Background: Mutations in eukaryotic translation initiation factor 2B (eIF2B) cause Childhood Ataxia with CNS Hypomyelination (CACH), also known as Vanishing White Matter disease (VWM), which is associated with a clinical pathology of brain myelin loss upon physiological stress. eIF2B is the guanine nucleotide exchange factor (GEF) of eIF2, which delivers the initiator tRNA(Met) to the ribosome. We recently reported that a R132H mutation in the catalytic subunit of this GEF, causing a 20% reduction in its activity, leads under normal conditions to delayed brain development in a mouse model for CACH/VWM.

A mouse model for eukaryotic translation initiation factor 2B-leucodystrophy reveals abnormal development of brain white matter.

Eukaryotic translation initiation factor 2B is a major housekeeping complex that governs the rate of global protein synthesis under normal and stress conditions. Mutations in any of its five subunits lead to leucoencephalopathy with vanishing white matter, an inherited chronic-progressive fatal brain disease with unknown aetiology, which is among the most prevalent childhood white matter disorders. We generated the first animal model for the disease by introducing a point mutation into the mouse Eif2b5 gene locus, leading to R132H replacement corresponding to the clinically significant human R136H mutation in the catalytic subunit.

Translational control of protein kinase Ceta by two upstream open reading frames.

Protein kinase C (PKC) represents a family of serine/threonine kinases that play a central role in the regulation of cell growth, differentiation, and transformation. Posttranslational control of the PKC isoforms and their activation have been extensively studied; however, not much is known about their translational regulation. Here we report that the expression of one of the PKC isoforms, PKCeta, is regulated at the translational level both under normal growth conditions and during stress imposed by amino acid starvation, the latter causing a marked increase in its protein levels.

Diverse poly(A) binding proteins mediate internal translational initiation by a plant viral IRES.

During 5'-cap-dependent translation, methylated 5'-cap and 3'-poly(A) tail work synergistically in a poly(A) binding protein (PABP)-dependent manner to facilitate translation via promoting the formation of a closed mRNA loop. On the other hand, during internal translation initiation, the requirement for and the roles of 3'-poly(A) tail and PABP vary depending on specific characteristics of each internal ribosomal entry site (IRES). In this study, we analyzed the effect of 3'-poly(A) tail and phylogenetically divergent PABPs on a polypurine tract-containing IRES element derived from the coat protein gene of crucifer-infecting tobamovirus (CrTMV IRES(CP)).