Biology subjects

Ranger, M.

Publications and source records attributed to Ranger, M..

2 recordsLinked to original sources

bioRxiv2021

Maternal separation affects fronto-cortical activity in rat pups during dam-pup interactions and behavioral transitions

Early-life stress is known to impair neurodevelopment. Prior work from our group showed that prolonged physical and emotional separation necessitated by the medical needs of preterm infants (born <37 weeks) is associated with lower electroencephalogram (EEG) power in frontal areas, and that trend can be reversed by an intervention that enhances the physical and emotional contact between preterm infant and mother. Here we sought to model the changes in preterm infant frontal EEG power in a rodent model. We examined effects of daily maternal separation (MS) on frontal cortex electrophysiological (electrocorticography [EcoG]) activity in neonatal rats. We also explored the effects of dam-pup behavioral interactions on EcoG activity. From postnatal days (P) 2-10, rat pups were separated daily from their dam and isolated from their littermates for 3 hours. Control rats were normally reared. On P10, pups were implanted with telemetry devices and an electrode placed on the left frontal dura. EcoG activity was recorded during daily sessions over the next four days while pups remained in the home cage, as well as in response to a pup-dam isolation-reunion paradigm at P12. EcoG power was computed in 1 Hz frequency bins between 1-100 Hz. Dam and pup behavioral interactions during recording sessions were coded and synchronized to EcoG data. MS pups showed lower EcoG power during dam-pup interactions. These data parallel human and provide evidence of lower fronto-cortical activity as an early marker of early-life stress and possible mechanism for long-term effects of maternal separation on neurobehavioral development.

neuroscience↗

bioRxiv2018

Combinatorial Genetic Control of Rpd3S through histone H3K4 and H3K36 Methylation in Budding Yeast

Much of euchromatin regulation occurs through reversible methylation of histone H3 lysine-4 and lysine-36 (H3K4me and H3K36me). Using the budding yeast Saccharomyces cerevisiae, we previously found that levels of H3K4me modulated temperature sensitive alleles of the transcriptional elongation complex Spt6-Spn1 through an unknown H3K4me effector pathway. Here we identify the Rpd3S histone deacetylase complex as the H3K4me effector underlying these Spt6-Spn1 genetic interactions. Exploiting these Spt6-Spn1 genetic interactions, we show that H3K4me and H3K36me collaboratively impact Rpd3S function in an opposing manner. H3K36me is deposited by the histone methyltransferase Set2 and is known to promote Rpd3S function at RNA PolII transcribed open reading frames. Using genetic epistasis experiments, we find that mutations perturbing the Set2-H3K36me-Rpd3S pathway suppress the growth defects caused by temperature sensitive alleles of SPT6 and SPN1, illuminating that this pathway antagonizes Spt6-Spn1. Using these sensitive genetic assays, we also identify a role for H3K4me in antagonizing Rpd3S that functions through the Rpd3S subunit Rco1, which is known to bind H3 N-terminal tails in a manner that is prevented by H3K4me. Further genetic experiments reveal that the H3K4 and H3K36 demethylases JHD2 and RPH1 mediate this combinatorial control of Rpd3S. Finally, our studies also show that the Rpd3L complex, which acts at promoter-proximal regions of PolII transcribed genes, counters Rpd3S for genetic modulation of Spt6-Spn1, and that these two Rpd3 complexes balance the activities of each other. Our findings present the first evidence that H3K4me and H3K36me act combinatorially to control Rpd3S.

genetics↗