B6N.129S4-Ddx25^tm1Mld/J

Stock number: 024751
Research areas: Developmental Biology Research, Reproductive Biology Research, Research Tools

Description

In these GRTH^-/- mice, a neo cassette replaces exons 6-7 and part of exon 5 of the (Ddx25) gene, abolishing gene expression. These mice may be useful for studying spermiogenesis and male infertility.

Detailed description

GRTH^-/- mice contain a neo cassette replacing exons 6-7 and part of exon 5 of the DEAD (Asp-Glu-Ala-Asp) box polypeptide 25 (Ddx25) gene, abolishing gene expression. Ddx25, also known as gonadotropin-regulated testicular RNA helicase (GRTH), is a testis-specific posttranscriptional regulator of genes that are essential for spermatid elongation and completion of spermiogenesis. GRTH is expressed in both somatic Leydig cells and germ cells. Female GRTH^-/- are fertile. Male homozygotes are sterile with azoospermia caused by a complete arrest of at step 8 spermiogenesis, which results in the failure of round spermatids to elongate. Males display normal gonadotropin and androgen profiles.

Development

A targeting vector was designed in the laboratory of Dr. Maria L Dufau (Molecular Endocrinology NICHD, NIH) to replace exons 6-7 and part of exon 5 encoding the DEAD (Asp-Glu-Ala-Asp) box polypeptide 25 (Ddx25) gene with a neomycin resistance (neo) cassette. The construct was electroporated into 129S4/SvJae-derived J1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and the resulting chimeric males were bred to C57BL/6N to generate a colony of GRTH^-/- mice. These mice were bred to C57BL/6N mice for at least 15 generations. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6NJ (Stock No. 005304) for at least one generation to establish the colony.

Allele

Symbol: Ddx25^tm1Mld
Name: targeted mutation 1, Maria L Dufau
MGI accession ID: MGI:3045804
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Ddx25
Marker name: DEAD (Asp-Glu-Ala-Asp) box polypeptide 25
Chromosome: 9
Strain of origin: 129S4/SvJae
Molecular note: This allele contains a mutation in the second ATG codon in exon 5, partial deletion of exon 5, and complete deletion of exons 6-7, which contain the conserved ATPase motif, G-GKT, and the PTRELA motif of the RNA helicase family. PCR analysis confirmed recombination and Northern and Western blot indicated lack of transcript and protein in mutant testes.