Macroorchidism in FMR1 Knockout Mice Is Caused by Increased Sertoli Cell Proliferation during Testicular Development1
The fragile X syndrome is the most frequent hereditary form of mental retardation. This X-linked disorder is, in most cases, caused by an unstable and expanding trinucleotide CGG repeat located in the 5′-untranslated region of the gene involved, the fragile X mental retardation 1 (FMR1) gene. Expans...
Saved in:
Published in | Endocrinology (Philadelphia) Vol. 139; no. 1; pp. 156 - 162 |
---|---|
Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Endocrine Society
01.01.1998
|
Online Access | Get full text |
Cover
Loading…
Summary: | The fragile X syndrome is the most frequent hereditary form of mental
retardation. This X-linked disorder is, in most cases, caused by an
unstable and expanding trinucleotide CGG repeat located in the
5′-untranslated region of the gene involved, the fragile X mental
retardation 1 (FMR1) gene. Expansion of the CGG repeat
to a length of more than 200 trinucleotides results in silencing of the
FMR1 gene promoter and, thus, in an inactive gene.
The clinical features of male fragile X patients include mental
retardation, autistiform behavior, and characteristic facial features.
In addition, macroorchidism is observed. To study the role of Sertoli
cell proliferation and FSH signal transduction in the occurrence of
macroorchidism in fragile X males, we made use of an animal model for
the fragile X syndrome, an Fmr1 knockout mouse.
The results indicate that in male Fmr1 knockout mice,
the rate of Sertoli cell proliferation is increased from embryonic day
12 to 15 days postnatally. The onset and length of the period of
Sertoli cell proliferation were not changed compared with those in the
control males. Serum levels of FSH, FSH receptor messenger RNA
expression, and short term effects of FSH on Sertoli cell function, as
measured by down-regulation of FSH receptor messenger RNA, were not
changed.
We conclude that macroorchidism in Fmr1 knockout male
mice is caused by an increased rate of Sertoli cell proliferation. This
increase does not appear to be the result of a major change in FSH
signal transduction in Fmr1 knockout mice. |
---|---|
ISSN: | 0013-7227 1945-7170 |
DOI: | 10.1210/endo.139.1.5706 |