Data for: Dietary nucleotides can prevent glucocorticoid-induced telomere attrition in a fast-growing wild vertebrate

Telomeres are chromosome protectors that shorten during eukaryotic cell
replication and in stressful conditions. Developing individuals are
susceptible to telomere erosion when their growth is fast and resources
are limited. This is critical because the rate of telomere attrition in
early life is linked to health and life span of adults. The metabolic
telomere attrition hypothesis (MeTA) suggests that telomere dynamics can
respond to biochemical signals conveying information about the
organism's energetic state. Among these signals are glucocorticoids,
hormones that promote catabolic processes, potentially impairing costly
telomere maintenance, and nucleotides, which activate anabolic pathways
through the cellular enzyme target of rapamycin (TOR), thus preventing
telomere attrition. During the energetically demanding growth phase, the
regulation of telomeres in response to two contrasting signals—one
promoting telomere maintenance and the other attrition—provides an ideal
experimental setting to test the MeTa. We studied nestlings of a rapidly
developing free-living passerine, the great tit (Parus major), that either
received glucocorticoids (Cort-chicks), nucleotides (Nuc-chicks), or a
combination of both (NucCort-chicks), comparing these with controls
(Cnt-chicks). As expected, Cort-chicks showed telomere attrition, while
NucCort- and Nuc-chicks did not. NucCort-chicks was the only group showing
increased expression of a proxy for TOR activation (the
gene telo2), of mitochondrial enzymes linked to ATP production
(cytochrome oxidase and ATP-synthase) and a higher efficiency in
aerobically producing ATP. NucCort-chicks had also a higher expression of
telomere maintenance genes (shelterin protein TERF2 and telomerase TERT)
and of enzymatic antioxidant genes (glutathione peroxidase and superoxide
dismutase). The findings show that nucleotide availability is crucial for
preventing telomere erosion during fast growth in stressful environments.