Kumar, Sandeep et al. (2015) International Worm Meeting "am117 delays somatic and reproductive aging in Caenorhabditis elegans by a mechanism that resembles caloric restriction."

Kornfeld, Kerry, Kocsisova, Zuzana, L. Schneider, Daniel, Kumar, Sandeep, Earnest, Asa

[International Worm Meeting, 2015]

A critical goal of aging research is the identification of genes and pathways that modulate somatic and reproductive aging. This information is important for understanding biological principles and may establish a foundation for interventions that can delay human aging. To analyze animal aging, we used C. elegans because it is a complex animal that is relevant to mammals, age-related degenerative changes in reproductive and somatic function are well established, and powerful genetic techniques are available.A forward genetic screen was used to identify mutants with delayed reproductive aging. The mutation am117 causes significant extensions of mated reproductive span and life span. Genetic mapping experiments were used to position the am117 mutation to an interval of chromosome I.We used whole genome sequencing to identify the am117 molecular lesion, a premature stop codon that affects one of several predicted transcripts from the locus. am117 affects a previously uncharacterized gene that encodes a protein that is homologous to human scaffold attachment factor B (SAFB1). am117 mutant animals displayed a 35-70% extension of somatic functions such as lifespan and >50% extension of reproductive span at multiple temperatures. Mutant animals also displayed robust delays of age-related degenerative changes and strong resistance to heat stress. To characterize the relationship with previously identified pathways that influence aging, we analyzed double mutant animals. Mutations that extend lifespan by affecting mitochondria, Insulin/IGF signaling and metabolic transcription factors were additive with am117, suggesting they function through independent mechanisms. By contrast, am117 was not additive with an eat-2(lf) mutation, a genetic model of caloric restriction caused by reduced pharyngeal pumping rates. am117 mutant animals displayed normal pharyngeal pumping rates but abnormal pharyngeal grinder morphology, raising the possibility that bacterial food may be ingested but not effectively absorbed. Consistent with a possible caloric restriction mechanism, we showed that pha-4/FOXOA and skn-1/NRF transcription factors are necessary for extension of lifespan caused by am117. The analysis of am117 may shed new light on caloric restriction, an important and conserved mechanism of lifespan extension.

Masahiro Miura et al. (2010) East Asia Worm Meeting "Analyses on the expression and function of a cytochrome b561 homolog C.ele1 in Caenorhabditis elegans."

Motonari Tsubaki, Masahiro Miura

[East Asia Worm Meeting, 2010]

Cytochrome b561 (b561) is a neuroendocrine vesicular membrane protein. Its function is regeneration of ascorbate (AsA), which is used as a cofactor for the biosynthesis of neurotransmitters or as an antioxidant for neurotransmitters. The transmembrane electron transfer catalyzed by b561 is very important for the maintenance of the nervous system. But unfortunately, precise mechanisms of the electron transfer reactions are not well understood. We have investigated on the molecular mechanisms of electron transfer and its physiological roles in the neuroendocrine system. In our present study, we focused on the C.elegans. C.elegans has only 302 neuron cells and is, therefore, a very attractive platform to conduct detailed studies concerning neuron-related proteins and enzymes. C.elegans has 6 types of homologs of b561, C.ele1 to 6. However, these homologs are not well studied. Among these homologs, C.ele1 is most likely to be expressed in neurons. Thus, C.ele1 was chosen as the first target to be studied. C.ele1 gene was isolated from a C.elegans cDNA library and was introduced to Pichia pastoris heterologous expression system. In a culturing, we could obtain C.ele1 protein. The visible absorption spectra of the partially-purified C.ele1 protein showed characteristic properties as a member of the b561 protein family and was found to be reducible with AsA.We, then, analyzed the expression of C.ele1 protein in the body of C.elegans with an immunohistochemical-staining technique. We found that C.ele1 protein was not expressed along the nervous system but in muscle tissues. Previous studies found that b561 proteins had many homologs and formed a big protein family. There are several b561 homologs whose functions yet to be established. Thus, C.ele1 may be a new type of the b561 protein family. In this regard, C.ele1 protein may have some important functions in muscles by utilizing AsA. It is known that some muscle cells produce collagen efficiently using AsA as cofactors. Thus, C.ele1 may help the biosynthesis of collagen. Importantly, our present result indicated further that other member of the b561 family in C.elegans might have a role for the supply of electron equivalents into neuroendcrine vesicles.