Retroposon compensatory mechanism hypothesis not supported: Zfa knockout mice are fertile.
Document Type
Article
Publication Date
2003
First Page
254
Last Page
260
JAX Source
Genomics 2003 Sep; 82(3):254-60.
Abstract
It is hypothesized that autosomal retroposons compensate for the loss of their inactivated essential X-chromosome progenitors during spermatogenesis. Here we test this Retroposon Compensatory Mechanism (RCM) hypothesis using the Zfy gene family. The mouse autosomal retroposon Zfa is expressed in testes at the same developmental time points at which Zfx levels decline, which correspond to the time of male sex chromosome inactivation, suggesting that Zfa may compensate for the loss of Zfx during spermatogenesis. We examined the effect of Zfa-targeted mutagenesis on spermatogenesis in three genetically distinct mouse strains. Surprisingly, Zfa knockout mice showed no detectable fertility, sperm count, or testes morphology defects. We therefore conclude that Zfa is not an essential gene for spermatogenesis and fertility. This surprising finding now challenges the RCM hypothesis at least for the Zfy gene family. It also forces us to reevaluate the original data underpinning the RCM hypothesis for this family and to propose alternative hypotheses.
Recommended Citation
Banks KG,
Johnson KA,
Lerner CP,
Mahaffey CL,
Bronson RT,
Simpson EM.
Retroposon compensatory mechanism hypothesis not supported: Zfa knockout mice are fertile. Genomics 2003 Sep; 82(3):254-60.