# Using microRNA-target chimeras to study post-transcriptional gene regulation in the mammalian CNS

> **NIH NIH F31** · JOHNS HOPKINS UNIVERSITY · 2021 · $46,036

## Abstract

Amongst the most intriguing and complex questions in neuroscience is that concerning the molecular
mechanisms by which synapses participate in learning and memory. Beginning as early as the 1960s, a growing
body of evidence indicates that new protein synthesis is required for learning and long-term memory formation.1
Additionally, it has been shown that activity-dependent protein synthesis is highly specific, as only a small subset
of available transcripts are translated following neuronal activity.2,3 There is also evidence that local protein
synthesis at synapses mediates plasticity and that perturbations in translation are associated with disorders of
cognitive function such as autism.4,5 The realization of the proximity of protein synthesis to the sites of synaptic
transmission, the specificity of transcripts that are translated, and its disruption in disease has underscored the
importance of understanding the nature of post-transcriptional regulatory mechanisms that shape the
complement of proteins in neurons and at synapses.
 Since their discovery in 1993, microRNAs (miRNAs) have been appreciated for their breadth of function
as post-transcriptional regulators of protein synthesis by translation inhibition and transcript destabilization.6
miRNAs regulate neuronal plasticity and dendritic spine morphogenesis, are implicated in higher-order brain
functions such as memory and cognitive dysfunction, and proteins involved in miRNA biogenesis and function
are found in neurons, including near synapses.1 The evolutionarily conserved let-7 family of miRNAs has
emerged as a critical mediator of post-transcriptional gene regulation in many growth-related processes including
developmental timing (C. elegans7 and D. melanogaster8,9), body axis programming (M. musculus10), metabolism
(M. musculus11), and cancer (M. musculus12 and H. sapiens13). The let-7 family of miRNAs are highly abundant
in mature differentiated neurons and work from our lab and others has shown that let-7 miRNA levels can be
regulated by neuronal activity3,14-16 and are disrupted in a mouse model lacking the fragile X mental retardation
protein (FMRP).31 However, an approach to unambiguously determine the genome-wide identity of mRNA
targets for let-7 and other miRNAs has not been possible until recently. This project employs a modified version
of the recently developed CLEAR-CLIP technique17 that involves cross-linking and immunoprecipitation followed
by intermolecular ligation of endogenous RNAs bound to Argonaute and high-throughput sequencing (CIMERA-
seq). CIMERA-seq will allow for critical miRNA targets and miRNA-regulatory mechanisms governing protein
synthesis in the mammalian CNS to be explored in great detail. The hypothesis of this proposal is that lowered
let-7 miRNA levels observed in vitro and in vivo in the FMRP-deficient brain will produce changes in the miRNA-
target profile consistent with altered neuronal plasticity, synapse overgrowth, and protein synthesis observ...

## Key facts

- **NIH application ID:** 10154004
- **Project number:** 1F31MH124282-01A1
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** William Thomas Mills
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $46,036
- **Award type:** 1
- **Project period:** 2020-12-21 → 2023-12-20

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10154004

## Citation

> US National Institutes of Health, RePORTER application 10154004, Using microRNA-target chimeras to study post-transcriptional gene regulation in the mammalian CNS (1F31MH124282-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10154004. Licensed CC0.

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