Taurine deficiency as a driver of aging.

Aging is associated with changes in circulating levels of various molecules, some of which remain undefined. We find that concentrations of circulating taurine decline with aging in mice, monkeys, and humans. A reversal of this decline through taurine supplementation increased the health span (the period of healthy living) and life span in mice and health span in monkeys. Mechanistically, taurine reduced cellular senescence, protected against telomerase deficiency, suppressed mitochondrial dysfunction, decreased DNA damage, and attenuated inflammaging. In humans, lower taurine concentrations correlated with several age-related diseases and taurine concentrations increased after acute endurance exercise. Thus, taurine deficiency may be a driver of aging because its reversal increases health span in worms, rodents, and primates and life span in worms and rodents. Clinical trials in humans seem warranted to test whether taurine deficiency might drive aging in humans.

Adaptive capacity to dietary Vitamin B12 levels is maintained by a gene-diet interaction that ensures optimal life span.

Diet regulates complex life-history traits such as longevity. For optimal lifespan, organisms employ intricate adaptive mechanisms whose molecular underpinnings are less known. We show that Caenorhabditis elegans FLR-4 kinase prevents lifespan differentials on the bacterial diet having higher Vitamin B12 levels. The flr-4 mutants are more responsive to the higher B12 levels of Escherichia coli HT115 diet, and consequently, have enhanced flux through the one-carbon cycle. Mechanistically, a higher level of B12 transcriptionally downregulates the phosphoethanolamine methyltransferase pmt-2 gene, which modulates phosphatidylcholine (PC) levels. Pmt-2 downregulation activates cytoprotective gene expression through the p38-MAPK pathway, leading to increased lifespan only in the mutant. Evidently, preventing bacterial B12 uptake or inhibiting one-carbon metabolism reverses all the above phenotypes. Conversely, supplementation of B12 to E. coli OP50 or genetically reducing PC levels in the OP50-fed mutant extends lifespan. Together, we reveal how worms maintain adaptive capacity to diets having varying micronutrient content to ensure a normal lifespan.

A 286 bp upstream regulatory region of a rice anther-specific gene, OSIPP3, confers pollen-specific expression in Arabidopsis.

OSIPP3 gene (coding for pectin methylesterase inhibitor protein) was isolated from a pre-pollinated inflorescence-specific cDNA library by differential screening of stage-specific libraries from Oryza sativa. OSIPP3 is present in the genome of rice as a single copy gene. OSIPP3 gene was expressed exclusively in the pre-pollinated spikelets of rice. Upstream regulatory region (URR) of OSIPP3 was isolated and a series of 5'-deletions were cloned upstream of GUS reporter gene and were used to transform Arabidopsis. OSIPP3_del1 and del2 transgenic plants showed GUS expression in root, anther and silique, while OSIPP3_del3 showed GUS activity only in anthers and siliques. Pollen-specific expression was observed in case of plants harboring OSIPP3_del4 construct. It can, therefore, be concluded that the OSIPP3 URR between -178 and +108 bp is necessary for conferring pollen-specific expression in Arabidopsis.

Overexpression of a zinc-finger protein gene from rice confers tolerance to cold, dehydration, and salt stress in transgenic tobacco.

Stress perception and signal transduction leading to tolerance involve a complex interplay of different gene products. We describe here the isolation and characterization of an intronless gene (OSISAP1) from rice encoding a zinc-finger protein that is induced after different types of stresses, namely cold, desiccation, salt, submergence, and heavy metals as well as injury. The gene is also induced by stress hormone abscisic acid. Overexpression of the gene in transgenic tobacco conferred tolerance to cold, dehydration, and salt stress at the seed-germination/seedling stage as reflected by the percentage of germination/green seedlings, the fresh weight of seedlings, and their developmental pattern. Thus, OSISAP1 seems to be an important determinant of stress response in plants.