# LOCATION AND FUNCTION OF M6A IN RETROVIRUS RNAS

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 1990 · $167,511

## Abstract

The major objective of the proposed research is to learn the functional
role(s) of modified nucleosides, predominantly N6-methyladenosine (m6A),
which are located at internal sites in most mRNAs of higher eukaryotes.
Previous studies, which led to the precise localization of m6As at seven
sites in RSV virion RNA, will be extended to RSV mRNAs.  If differences in
methylation patterns are observed between the genomic RNA and specific
viral mRNAs, the significance of m6A in regulation of either splicing or
packaging of viral RNA will be investigated.  Oligonucleotide-directed
mutagenesis will be used to prevent methylation at specific sites in RSV
RNA, and the effects of altering the methylation pattern will be
investigated both in vivo and in vitro.  Possible effects on RNA splicing,
transport from the nucleus, packaging into virions, reverse transcription,
translation, RNA secondary and tertiary structure, and stability will be
examined.  Purified m6A methylase will also be used in in vitro studies of
the biological function of m6A, as well as in studies of the specificity of
m6A modification.  A consensus sequence for m6A sites will be derived for
chicken cellular mRNAs and compared with that previously observed for
mammalian mRNAs (RAC) and for RSV RNA (RGACU), to determine whether there
are species-specific differences in m6A sites.  The hypothesis that m6A at
potential branch points affects splicing at nearby splice acceptor sites
will be tested.  Intron branches, which form lariat structures during mRNA
splicing, usually occur at adenines, preceded by a purine and followed by a
pyrimidine.  This sequence is similar to the m6A consensus sequence.
Therefore, it is possible that m6A is present at branch points and promotes
2'-P-5' lariat bond formation or alternatively that m6A at a potential
branch point may block lariat formation.  Branch structures will be
isolated from total nuclear poly (A)+ RNA, and the relative amount of m6A
will be measured directly.  The presence of m6A elsewhere in intron
sequences will also be examined to determine whether m6A is totally
conserved during mRNA processing.  These studies may give insight into
regulation of retroviral RNA metabolism, as well as into that of cellular
mRNAs.

## Key facts

- **NIH application ID:** 3171145
- **Project number:** 5R01CA033199-08
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **SAM.gov UEI:** FTMTDMBR29C7
- **Principal Investigator:** Karen L. Beemon
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1990
- **Award amount:** $167,511
- **Award type:** 5
- **Project period:** 1982-07-01 → 1992-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3171145

## Citation

> US National Institutes of Health, RePORTER application 3171145, LOCATION AND FUNCTION OF M6A IN RETROVIRUS RNAS (5R01CA033199-08). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3171145. Licensed CC0.

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