The WD40-repeat containing proteins, including DDB1–CUL4-associated factors (DCAFs), are abundant and conserved proteins that play important roles in different cellular processes including spermatogenesis. DCAFs are subset of WD40 family proteins that contain WDxR motif and have been proposed to function as substrate receptor for Cullin4-RING-based E3 ubiquitin ligase complexes to recruit diverse proteins for ubiquitination, a vital process in spermatogenesis. Large number of WD40 genes has been identified in different species including mouse and human. However, a systematic expression profiling of WD40 genes in different tissues of mouse and human has not been investigated. We hypothesize that large number of WD40 genes may express highly or specifically in the testis, where their expression is uniquely regulated during testis development and spermatogenesis. Therefore, the objective of this study is to mine and characterize expression patterns of WD40 genes in different tissues of mouse and human with particular emphasis on DCAF genes expressions during mouse testicular development. Publically available RNA sequencing (RNA seq) data mining identified 347 and 349 WD40 genes in mouse and human, respectively. Hierarchical clustering and heat map analyses of RNA seq datasets revealed differential expression patterns of WD40 genes with around 60–73% of the genes were highly or specifically expressed in testis. Similarly, around 74–83% of DCAF genes were predominantly or specifically expressed in testis. Moreover, WD40 genes showed distinct expression patterns during embryonic and postnatal testis development in mice. Finally, different germ cell populations of testis showed specific patterns of WD40 genes expression. Predicted gene ontology analyses revealed more than 80% of these proteins are implicated in cellular, metabolic, biological regulation and cell localization processes. We have identified large number of WD40 family genes that are highly or specifically expressed in the testes of mouse and human. Moreover, WD40 genes have distinct expression patterns during embryonic and postnatal development of the testis in mice. Further, different germ cell populations within the testis showed specific patterns of WD40 genes expression. These results provide foundation for further research towards understanding the functional genomics and molecular mechanisms of mammalian testis development and spermatogenesis.

中文翻译：

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WD40家族基因（包括DDB1和CUL4相关因子（DCAF）基因）在小鼠和人类中的表达谱表明，在睾丸发育和精子形成中具有重要的调节作用。

包含WD40重复序列的蛋白质，包括DDB1–CUL4相关因子（DCAF），是丰富且保守的蛋白质，在包括精子发生在内的不同细胞过程中起着重要作用。DCAF是WD40家族蛋白的子集，该蛋白包含WDxR模体，已被提议充当基于Cullin4-RING的E3泛素连接酶复合物的底物受体，以募集各种蛋白进行泛素化，这是精子发生的重要过程。已经在包括小鼠和人类的不同物种中鉴定出大量的WD40基因。但是，尚未研究WD40基因在小鼠和人不同组织中的系统表达谱。我们假设大量WD40基因可能在睾丸中高表达或特异性表达，在睾丸发育和生精过程中，它们的表达受到独特调节。因此，本研究的目的是在小鼠和人的不同组织中挖掘和表征WD40基因的表达模式，并特别强调小鼠睾丸发育过程中DCAF基因的表达。公开可用的RNA测序（RNA seq）数据挖掘分别在小鼠和人类中鉴定出347和349个WD40基因。通过对RNA seq数据集进行分层聚类和热图分析，发现WD40基因的差异表达模式，其中60-73％的基因在睾丸中高度表达或特异性表达。同样，约74–83％的DCAF基因在睾丸中主要或特异性表达。此外，WD40基因在小鼠胚胎和出生后睾丸发育过程中显示出不同的表达模式。最后，不同的睾丸生殖细胞群显示了WD40基因表达的特定模式。预测的基因本体分析表明，这些蛋白质中有80％以上与细胞，代谢，生物调节和细胞定位过程有关。我们已经鉴定了在小鼠和人类的睾丸中高度或特异性表达的大量WD40家族基因。此外，WD40基因在小鼠睾丸的胚胎和出生后发育过程中具有不同的表达模式。此外，睾丸内的不同生殖细胞群体显示出WD40基因表达的特定模式。