# HORMONAL REGULATION OF THE INSECT EPIDERMIS

> **NIH NIH R01** · UNIVERSITY OF WASHINGTON · 1993 · $211,041

## Abstract

Our long-term goal is to understand how ecdysteroids and juvenile hormone
(JH) act to coordinate insect growth and development.  Ecdysteroids cause
molting, both suppressing on-going intermolt gene expression and activating
the cascade of genes necessary for the molt.  Moreover, ecdysteroids are
important for maintenance of tissue synchrony during the molt.  JH
determines whether the molt will be progressive or not; in its presence
metamorphosis cannot occur.  Thus, JH prevents ecdysteroid's activation of
previously unexpressed genes that allow the cell to change its
differentiated state.  Our model for studying this action is the insect
epidermis which makes the cuticle, i.e. the exoskeleton, and which is a
single cell layer thick and can readily be cultured.  Our specific aims for
the next 5 years are:  1) To characterize the regulatory regions of the
several larval cuticular genes and dopa decarboxylase and to study their
possible interactions with ecdysteroid and JH receptors and/or the
transcription factors that these hormones induce.  2) To clone,
characterize, and study the hormonal control of a pupal-specific cuticle
gene to complete our arsenal of epidermal genes that are hormonally
regulated at metamorphosis.  3) To determine the role in molting and
metamorphosis of the ecdysteroid-induced transcription factor ("RAR") that
shows significant similarity to the mammalian retinoic acid receptor.  4)
To examine possible changes in EcR subtypes in the epidermis through larval
molting and metamorphosis by in situ hybridization and immunocytochemistry
and how they are regulated by the hormonal milieu.  These studies will
allow us to define at the molecular level how ecdysteroids and JH regulate
insect growth, molting, and metamorphosis.  This information can lead to
design of new types of insect growth regulators essential to the control of
disease vectors.  Also, emerging similarities between the actions of JH and
of retinoic acid in the regulation of cell differentiation, particularly in
mammalian epidermis, make the insect epidermis a possible nonvertebrate
model for study of common mechanisms involved.

## Key facts

- **NIH application ID:** 3125191
- **Project number:** 5R01AI012459-18
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **SAM.gov UEI:** HD1WMN6945W6
- **Principal Investigator:** LYNN M RIDDIFORD
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $211,041
- **Award type:** 5
- **Project period:** 1979-01-01 → 1996-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3125191

## Citation

> US National Institutes of Health, RePORTER application 3125191, HORMONAL REGULATION OF THE INSECT EPIDERMIS (5R01AI012459-18). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3125191. Licensed CC0.

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