# BIOLOGY OF THE TESTIS

> **NIH NIH R01** · DUKE UNIVERSITY · 1994 · $273,141

## Abstract

The overall goals of the proposed research are to examine regulatory
mechanisms that influence post-mitotic development of testicular germ
cells. The major calcium binding protein in mammalian sperm is
calspermin. We have cloned the CDNA encoding this protein. Analysis of
the sequence and of the gene revealed that calspermin is derived from a
transcription unit that also encodes a novel calcium-calmodulin
dependent protein kinase. This cDNA has also been cloned and sequenced.
Whereas the kinase mRNA is first detected in early primary spermatocytes
and declines to a low level following the last meiotic division,
calspermin mRNA is first expressed in pachytene primary spermatocytes
and continues to increase as cell complete meiosis and undergo terminal
differentiation. We have isolated genomic DNA that encodes the entire
transcription unit and propose to characterize the structural
organization of the gene. We will then utilize transfected mammalian
cells, a testicular transcription system and transgenic mice to
determine the molecular mechanisms that control cell specific mRNA
expression. The hypothesis is that alternative transcriptional
initiation followed by a requisite unique RNA processing event are
involved in calspermin production. Expression vectors have been used to
produce calspermin and the kinase and to identify key amino acids
required for function and/or regulation of activity. A constitutive
kinase has been used to develop mammalian cell lines that express the
enzyme in a regulated fashion and to identify a transcriptional DNA
element that is trans-activated by the active enzyme. We propose to
characterize the mechanism by which the overexpression of the kinase
results in a G2 cell cycle block and the transcription factor responsive
to the kinase. Transgenic mice will be utilized to evaluate the
consequences of altering the concentration of the kinase on
spermatogenesis and sperm motility. Different promoters will be employed
to change the temporal expression and/or amount of the proteins during
germ cell development. We predict that the kinase will play a role in
the onset, progression or completion of meiosis whereas calspermin will
be involved in terminal differentiation of the spermatid or sperm
motility.

## Key facts

- **NIH application ID:** 2195810
- **Project number:** 5R01HD007503-21
- **Recipient organization:** DUKE UNIVERSITY
- **SAM.gov UEI:** TP7EK8DZV6N5
- **Principal Investigator:** ANTHONY R MEANS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $273,141
- **Award type:** 5
- **Project period:** 1977-05-01 → 1997-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2195810

## Citation

> US National Institutes of Health, RePORTER application 2195810, BIOLOGY OF THE TESTIS (5R01HD007503-21). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2195810. Licensed CC0.

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