# REGULATION OF PRONUCLEAR DEVELOPMENT

> **NIH NIH R01** · UNIVERSITY OF IOWA · 1993 · $105,198

## Abstract

The proposed research will test the hypothesis that following its
incorporation into the egg, enlargement of the sperm nucleus is
coordinated with the activity of the maternal chromatin, i.e., changes
in nucleoplasmic interactions affecting the status/function of the
maternal chromatin also influence the pattern of sperm nuclear
enlargement at fertilization.  Formulation of such a hypothesis is based
on recent observations demonstrating that sperm nuclear enlargement does
not proceed at a uniform rate in eggs inseminated at an arrested stage
of meiosis but consists of phases, temporally correlated with major
changes in the activity of the maternal chromatin.  The presence of
distinct phases in the rate of sperm nuclear enlargement suggests that
different regulatory processes occur in a specific sequence and are
responsible for transforming the sperm nucleus into a pronucleus.  The
possible mechanisms which comprise each of these phases, how they are
regulated and related to one another and conditions modulating activity
of the maternal chromatin are aspects to be explored.  Investigations
will be conducted to determine the kinetics of sperm nuclear enlargement
in eggs that can be inseminated at different periods of meiotic
maturation.  Meiotic maturation of the maternal chromatin will be
perturbed by agents having known mechanisms of action, e.g., metabolic
and protein synthesis inhibitors, and the rates of sperm nuclear
enlargement will be analyzed.  In conjunction with these investigations
studies will be carried out to examine the possible relation of specific
proteins, newly synthesized during fertilization, to processes of
meiotic maturation and sperm nuclear transformations.  These studies
will provide further evidence that specific periods of sperm nuclear
enlargement are coupled with the status (condensed/dispersed) of the
maternal chromatin.  Possible mechanisms regulating sperm nuclear
transformations, meiotic maturation, and how the male- and female-
derived chromatin become synchronized with respect to events involving
first mitosis and the initiation of cell cycle events characteristic of
cleaving embryos will be elucidated.

## Key facts

- **NIH application ID:** 2197211
- **Project number:** 5R01HD015510-12
- **Recipient organization:** UNIVERSITY OF IOWA
- **SAM.gov UEI:** Z1H9VJS8NG16
- **Principal Investigator:** FRANK J LONGO
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $105,198
- **Award type:** 5
- **Project period:** 1981-09-01 → 1995-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2197211

## Citation

> US National Institutes of Health, RePORTER application 2197211, REGULATION OF PRONUCLEAR DEVELOPMENT (5R01HD015510-12). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2197211. Licensed CC0.

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