Modeling human male infertility in mice

描述（由申请人提供）：估计有15%的夫妇受到不孕症的影响。男性和女性对不孕症的贡献大致相等。生育力的调节显然是复杂的，因为已经描述了200多只基因敲除小鼠具有不育作为主要表型。尽管在小鼠模型方面取得了进展，但人类男性不育的遗传原因很少被确定。人类不孕症遗传原因研究进展缓慢可归因于两个因素：1）特定基因中的致病突变预计极为罕见; 2）因果关系几乎不可能证明，因为传统的基于谱系的连锁分析不适用，由于不孕症导致的后代缺乏。显然，需要新的方法来研究人类不育的遗传原因。因此，我们建议，最翔实的方式来提高我们的知识，人类男性不育是利用敲入技术，以产生和表征小鼠，窝藏类似的人类突变。我们最近证明了TAF 7 L，一种X染色体编码的转录因子，在小鼠精子生成中起着关键作用。为了确定TAF 7 L是否也在人类不育中发挥作用，我们筛选了>100名不育男性，并鉴定了一个单一的氨基酸取代（D？G）在具有低精子计数的不育男性中的TAF 7 L。我们的酵母遗传学研究表明，这种保守的天冬氨酸残基是TAF 7（TAF 7 L的酵母同源物）功能所必需的。为了明确确定它是否在男性不育中起致病作用，我们将在敲入小鼠中表达类似突变，使得仅表达突变的TAF 7 L。如果TAF 7 L中的单个点突变确实足以降低男性生育力，那么它将代表第一个被鉴定的在人类男性不育中起致病作用的单基因突变。这一发现的意义是双重的。首先，TAF 7 L突变可能是母系遗传的，应该在遗传咨询中考虑：因为这是一个X连锁基因，一个单一的突变会使男性不育。第二，由于TAF 7 L是一种转录因子，未来的研究，以确定受这种突变影响的蛋白质-蛋白质相互作用可以提供显着的洞察生殖细胞中的独特的转录程序。 不孕症是一个普遍的生殖健康问题，影响着美国数百万对夫妇。该项目的完成将确定某些人类男性不育病例的遗传原因。

DESCRIPTION (provided by applicant): An estimated 15% of couples are affected by infertility worldwide. Males and females contribute roughly equally to infertility. The regulation of fertility is clearly complex, as more than 200 knockout mice have been described to have infertility as a major phenotype. Despite progress made in mouse models, few genetic causes of male infertility in humans have been identified. The slow progress in the study of genetic causes of infertility in humans can be attributed to two factors: 1) causative mutations in a particular gene are expected to be extremely rare; and 2) causality is nearly impossible to prove, as traditional pedigree-based linkage analysis is not applicable, due to the lack of offspring caused by infertility. Clearly new approaches are required to investigate genetic causes of human infertility. Accordingly, we propose that the most informative way to advance our knowledge of human male infertility is to utilize knockin technology to generate and characterize mice that harbor the analogous human mutation. We have recently demonstrated that TAF7L, an X chromosome-encoded transcription factor, plays a critical role in sperm production in mice. To determine if TAF7L could also play a role in human infertility, we screened >100 infertile men and identified a single amino acid substitution (D?G) in TAF7L in an infertile man with low sperm count. Our yeast genetic studies demonstrated that this conserved aspartic residue is required for the function of TAF7, yeast homologue of TAF7L. To definitively determine if it plays a causative role in male infertility, we will express the analogous mutation in knockin mice such that only the mutated TAF7L is expressed. If a single point mutation in TAF7L is indeed sufficient to reduce male fertility, it will represent the first identified single gene mutation to play a causative role in male infertility in humans. The significance of such a finding will be two-fold. First, TAF7L mutations could be maternally inherited and should be considered in genetic counseling: since this is an X- linked gene, a single mutation would render males sterile. Second, as TAF7L is a transcription factor, future studies to determine protein-protein interactions affected by this mutation could provide significant insight into the unique transcription programs in germ cells. PUBLIC HEALTH RELEVANCE: Infertility is a widespread reproductive health problem affecting millions of couples in the US. Completion of this project will identify the genetic cause of some cases of male infertility in humans.