Regulated nucleocytoplasmic transport in spermatogenesis: a driver of cellular differentiation?
This review explores the hypothesis that regulation of nucleocytoplasmic shuttling is a means of driving differentiation, using spermatogenesis as a model. The transition from undifferentiated spermatogonial stem cell to terminally differentiated spermatozoon is, at its most basic, a change in the repertoire of expressed genes. To effect this, the complement of nuclear proteins, such as transcription factors and chromatin remodelling components must change. Current knowledge of the nuclear proteins and nucleocytoplasmic transport machinery relevant to spermatogenesis is consolidated in this review, and their functional linkages are highlighted not only as a means of regulating nuclear protein composition, but also as a key mechanism regulating gene transcription and hence cell fate. Through this, we hypothesize that male germ cell differentiation is mediated through regulation of nuclear transport machinery components, and thereby of the access of critical factors to the nucleus. The importance of nucleocytoplasmic trafficking to male germ cell differentiation is discussed, using the sex-determining factors Sry and SOX9, cell cycle regulators, CREM and cofactors and the Smads as specific examples, together with the roles in gametogenesis for particular nuclear transport factors in Caenorhabditis elegans and Drosophila.
Hogarth
Cathryn
C
Monash Institute of Medical Research, Monash University, Melbourne, Australia.
Itman
Catherine
C
Jans
David A
DA
Loveland
Kate L
KL
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000818:Animals; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D053823:Hedgehog Proteins; D006609:High Mobility Group Proteins / Q000378:metabolism; D028884:Karyopherins / Q000235:genetics / Q000378:metabolism; D008297:Male; D028861:Nuclear Pore Complex Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D050814:Octamer Transcription Factor-3; D055758:SOX9 Transcription Factor; D051876:Sex-Determining Region Y Protein; D051785:Smad Proteins; D013091:Spermatogenesis / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology; D013234:Stem Cells / Q000502:physiology; D013737:Testis / Q000166:cytology / Q000502:physiology; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D053823:Hedgehog Proteins; D006609:High Mobility Group Proteins; D028884:Karyopherins; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D050814:Octamer Transcription Factor-3; D055758:SOX9 Transcription Factor; D051876:Sex-Determining Region Y Protein; D051785:Smad Proteins; D015534:Trans-Activators; D014157:Transcription Factors