# MATERNAL MRNA LOCALIZATIONS IN A DETERMINATE EGG

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA AT DAVIS · 1994 · $158,808

## Abstract

Embryonic development is initiated by the activity of ooplasmic
determinants.  Some of these determinants are localized mRNA molecules,
yet few such mRNAs have been identified and the mechanisms involved in
their localization and function are poorly understood.  The long term
objective of this study is to understand the role of maternal mRNAs in
the initiation of embryonic development.  Eggs and embryos of ascidians,
which contain cytoplasmic regions with distinct developmental fates, are
used as a model system.  This proposal exploits unique attributes of
ascidians, including the ability to isolate an egg cytoplasmic region
containing localized mRNAs, the autonomous and precocious differentiation
of muscle cells during embryogenesis, and the existence of sibling
species with radically different modes of development, to identify and
characterize developmentallysignificant maternal mRNAs.  I have already
cloned several mRNAs that are localized in the myoplasm, a egg
cytoplasmic region that specifies embryonic axis and muscle cell
development, and one mRNA that is localized in the ectoplasm, a region
inherited by ectodermal cells.  At least one of the mRNAs localized in
the myoplasm is associated with the egg cytoskeletal matrix.  This
proposal of six specific aims is designed to continue and extend this
work.  The first specific aim is to identify localized and other maternal
mRNAs that are candidates for ooplasmic determinants.  This will be done
by screening cDNA libraries for (1) clones encoding mRNAs localized in
the myoplasm, (2) clones encoding an mRNA localized in the ectoplasm, and
(3) clones homologous to the vertebrate myogenic genes, MyoD and
myogenin, which may be involved in muscle development; and (4) screening
a subtracted cDNA library for clones with messages expressed in eggs of
an ascidian species exhibiting larval development but not in eggs of a
sibling species lacking larval development The second specific aim is to
characterize the mRNAs by sequencing and determining their temporal and
spatial expression during development.  The third specific aim is to
determine whether the expression of these mRNAs is changed in the species
lacking larval development.  The fourth specific aim is to determine
whether these mRNAs are associated with the egg cytoskeletal matrix and
whether this association is altered in the species lacking larval
development.  The fifth specific aim is to identify and characterize
proteins encoded by these mRNAs with respect to their temporal and
spatial expression during development and whether changes in expression
patterns occur in the species lacking larval development.  The sixth
specific aim is to test the function of each mRNA by microinjecting
synthetic transcripts into LTV irradiated eggs, which lack functional
axial determinants, and eggs of the species lacking larval development,
which are defective in muscle determinants.

## Key facts

- **NIH application ID:** 2197054
- **Project number:** 5R01HD013970-15
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **SAM.gov UEI:** TX2DAGQPENZ5
- **Principal Investigator:** WILLIAM R JEFFERY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $158,808
- **Award type:** 5
- **Project period:** 1980-08-01 → 1996-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2197054

## Citation

> US National Institutes of Health, RePORTER application 2197054, MATERNAL MRNA LOCALIZATIONS IN A DETERMINATE EGG (5R01HD013970-15). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2197054. Licensed CC0.

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