Cloning and Characterization of Gonadotropin-Inducible Ovarian Transcription Factors (GIOT1 and -2) That Are Novel Members of the (Cys)2-(His)2-Type Zinc Finger Protein Family
Gonadotropins are essential for ovarian follicular development and differentiation. To identify genes that are rapidly induced by gonadotropin in the immature rat ovary, ovarian genes were screened by a subtraction cloning procedure. cDNA clones encoding novel members of the (Cys)2-(His)2-type zinc...
Gespeichert in:
Veröffentlicht in: | Molecular endocrinology (Baltimore, Md.) Md.), 2001-10, Vol.15 (10), p.1693-1705 |
---|---|
Hauptverfasser: | , , , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | Gonadotropins are essential for ovarian follicular development and
differentiation. To identify genes that are rapidly induced by
gonadotropin in the immature rat ovary, ovarian genes were screened by
a subtraction cloning procedure. cDNA clones encoding novel members of
the (Cys)2-(His)2-type zinc finger protein
family GIOT1 and -2 (gonadotropin-inducible transcription factor 1 and
2), were identified. Two isoforms of GIOT2 (GIOT2α and 2β), which
are probably produced by alternative splicing, also exist. Nucleotide
sequence analysis revealed that GIOT1, but not GIOT2, contains the
krüppel-associated box-A domain at the NH2 terminus.
RNA analyses revealed that these mRNAs were rapidly and temporarily
induced by gonadotropins in the rat testis as well as in the ovary.
In situ hybridization study revealed that expression of
GIOT1 was induced in theca interna cells in the ovary and Leydig cells
in the testis. Interestingly, the gene expression of GIOT1 is
restricted to the pituitary, adrenal, testis, and ovary, while GIOT2
gene is expressed ubiquitously. A functional analysis of GIOT1 and -2
by a GAL4-based mammalian one-hybrid system revealed that GIOT1, but
not GIOT2, is a transcriptional repressor and that the
krüppel-associated box-A domain of GIOT1 is responsible for the
transcriptional repressor activity. A GAL4-based yeast two-hybrid
system was also used to identify proteins that interact with the rat
GIOT1. We cloned genes encoding rat homologs of human I-mfa domain
containing protein and transcriptional intermediary factor 1 β, both
of which are transcription-regulatory proteins. Interaction of these
proteins with GIOT1 was directly demonstrated by GST pull-down assay.
Our data strongly suggest that GIOT1 may function as a novel
transcriptional repressor by working with rat homologs of human I-mfa
domain containing protein and transcriptional intermediary factor 1β
proteins and may play a significant role at the transcription level in
the folliculogenesis. |
---|---|
ISSN: | 0888-8809 1944-9917 |
DOI: | 10.1210/mend.15.10.0718 |