# RIBOSOMAL FORMATION DURING MYOBLAST DIFFERENTIATION

> **NIH NIH R01** · UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA · 1988 · $139,363

## Abstract

Our previous experiments indicate that the transcription of ribosomal DNA
(rDNA) and ribosomal protein (r-protein) genes are reduced 3-6 fold and the
translational efficiencies or r-protein mRNAs are reduced 1.3-1.6 fold
after proliferating mouse myoblasts differentiate into muscle fibers.  This
grant proposes to identify the extracellular signals triggering these
decreases and to identify the sequences in r-protein genes and r-protein
mRNAs that are involved in regulating these decreases.  To determine if
these decreases actually occur coordinately, the transcription of S16, L18
and L32 r-protein genes and the translational efficiencies of S16, L18, and
L32 r-protein mRNAs will be measured in non-proliferating cultures of
myoblasts undergoing highly synchronous differentiation.  These
measurements will also be made in non-dividing, but non-differentiating
myoblasts cultures to determine if these decreases are dependent on
myoblast differentiation or upon the cessation of myoblast cell division.
In these experiments transcriptional rates will be measured in nuclear
transcription reactions, and the translational efficiencies of r-protein
mRNAs will be inferred from the polysomal distribution of r-protein mRNAs.
The sequences in the L32 r-protein gene that are involved in regulating its
transcription during myoblast differentiation will be identified using
deletion/replacement mapping and cell transformation techniques.  A series
of L32 r-protein-neomycin chimeric plasmids will be constructed that differ
into the sequence content of the L32 r-protein gene.  These will be stably
introduced in myoblasts.  The transcription of the r-protein-neomycin
chimeric gene will be measured in nuclear transcription reactions from
these transformed myoblasts and fibers.  The same strategy will be used to
identify the sequences in L32 r-protein mRNA that control the decreased
translational efficiency of this mRNA during myoblast differentiation.  In
this case the translational efficiency of the chimeric l32
r-protein-neomycin mRNAs will be measured.  Further, to determine if the
transcription of rRNA or r-protein genes and the translation of r-protein
mRNAs are regulated by the intracellular concentrations of rRNA, r-protein
mRNAs or r-proteins, myoblast cell lines will be constructed that
overproduce either rRNA or r-proteins.  The transcription of rRNA and S16,
L18, and L32 r-protein genes and the translational efficiencies of S16,
L18, and L32 r-protein mRNAs will be measured in myoblasts and fibers of
these overproducing lines.

## Key facts

- **NIH application ID:** 3156241
- **Project number:** 5R01AR032221-06
- **Recipient organization:** UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA
- **SAM.gov UEI:** J22LNTMEDP73
- **Principal Investigator:** LEWIS H BOWMAN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $139,363
- **Award type:** 5
- **Project period:** 1983-05-01 → 1990-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3156241

## Citation

> US National Institutes of Health, RePORTER application 3156241, RIBOSOMAL FORMATION DURING MYOBLAST DIFFERENTIATION (5R01AR032221-06). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3156241. Licensed CC0.

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