Mice that are homozygous for the targeted mutation are viable, normal in size and do not display any gross physical or behavioral abnormalities. No gene product (protein) is detected in testicular homogenates. Levels of transition nuclear protein 2 and protamine 2 precursor are elevated. Homozygous female mice are fertile. Homozygous male mice are subfertile, approximately 60% are infertile, and display diminished sperm motility, sperm tail abnormalities and sperm chromatin abnormalities. Electron microscopy analysis of spermatids reveals both abnormal large rod-like chromatin condensation units as well as normal fine fibrillar chromatin morphology. This mutant mouse strain may be useful in studies of male infertility and/or subfertility.
A targeting vector containing neomycin resistance and thymidine kinase genes was used to replace the entire targeted gene. The construct was electroporated into 129S7/SvEvBrd-Hprt+ derived AB1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting male chimeric animals were backcrossed to 129S6/SvEvTac female mice.
|Allele Name||targeted mutation 1, Marvin L Meistrich|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||Tnp1-; Tnp1-null|
|Gene Symbol and Name||Tnp1, transition protein 1|
|Strain of Origin||129S7/SvEvBrd-Hprt+|
|Molecular Note||The entire gene was replaced with a neomycin cassette, which was inserted in an antisense orientation. Tnp1 protein was not detectable in extracts of testicular homogenates from homozygous mutant mice.|
|Mutations Made By|| |
Dr. Marvin Meistrich, University of Texas M.D. Anderson Cancer
This strain originated on a 129S7 background, has been backcrossed to the 129S6/SvEvTac background and is maintained as heterozygous males and homozygous females.
When using the Tnp1 KO mouse strain in a publication, please cite the originating article(s) and include JAX stock #004511 in your Materials and Methods section.