An RNA Binding Regulatory Cascade Controls the Switch from Proliferation to Differentiation in the Male Germ Cell Lineage

Overview

Journal bioRxiv

Date 2024 Sep 16

PMID 39282418

Authors

Devon E Harris

Jongmin J Kim

Sarah R Stern

Hannah M Vicars

Neuza R Matias

Lorenzo Gallicchio

Catherine C Baker

Margaret T Fuller

Affiliations

Soon will be listed here.

Abstract

The switch from precursor cell proliferation to onset of differentiation in adult stem cell lineages must be carefully regulated to produce sufficient progeny to maintain and repair tissues, yet prevent overproliferation that may enable oncogenesis. In the male germ cell lineage, spermatogonia produced by germ line stem cells undergo a limited number of transit amplifying mitotic divisions before switching to the spermatocyte program that sets up meiosis and eventual spermatid differentiation. The number of transit amplifying divisions is set by accumulation of the (Bam) protein to a critical threshold. In mutants, spermatogonia proliferate through several extra rounds of mitosis then die without becoming spermatocytes. Here we show that a key role of Bam for the mitosis to differentiation switch is repressing expression of Held Out Wings (), homolog of mammalian Quaking. Knockdown of in germ cells was sufficient to allow spermatogonia mutant for or its partner () to differentiate, while forced expression of nuclear-targeted How protein in spermatogonia wild-type for resulted in continued proliferation at the expense of differentiation. Our findings suggest that Bam targets RNA for degradation by acting as an adapter to recruit the CCR4-NOT deadenylation complex via binding its subunit, Caf40. As How is itself an RNA binding protein with roles in RNA processing, our findings reveal that the switch from proliferation to meiosis and differentiation in the male germ line adult stem cell lineage is regulated by a cascade of RNA-binding proteins.

References

Li H, Janssens J, De Waegeneer M, Kolluru S, Davie K, Gardeux V . Fly Cell Atlas: A single-nucleus transcriptomic atlas of the adult fruit fly. Science. 2022; 375(6584):eabk2432. PMC: 8944923. DOI: 10.1126/science.abk2432. View

Insco M, Bailey A, Kim J, Olivares G, Wapinski O, Tam C . A self-limiting switch based on translational control regulates the transition from proliferation to differentiation in an adult stem cell lineage. Cell Stem Cell. 2012; 11(5):689-700. PMC: 3833810. DOI: 10.1016/j.stem.2012.08.012. View

Liao Y, Smyth G, Shi W . featureCounts: an efficient general purpose program for assigning sequence reads to genomic features. Bioinformatics. 2013; 30(7):923-30. DOI: 10.1093/bioinformatics/btt656. View

Kim J, Lu C, Srinivasan S, Awe S, Brehm A, Fuller M . Blocking promiscuous activation at cryptic promoters directs cell type-specific gene expression. Science. 2017; 356(6339):717-721. PMC: 5572561. DOI: 10.1126/science.aal3096. View

Monk A, Siddall N, Volk T, Fraser B, Quinn L, McLaughlin E . HOW is required for stem cell maintenance in the Drosophila testis and for the onset of transit-amplifying divisions. Cell Stem Cell. 2010; 6(4):348-360. DOI: 10.1016/j.stem.2010.02.016. View

Chen D, Wu C, Zhao S, Geng Q, Gao Y, Li X . Three RNA binding proteins form a complex to promote differentiation of germline stem cell lineage in Drosophila. PLoS Genet. 2014; 10(11):e1004797. PMC: 4238977. DOI: 10.1371/journal.pgen.1004797. View

Bedbrook C, Nath R, Nagvekar R, Deisseroth K, Brunet A . Rapid and precise genome engineering in a naturally short-lived vertebrate. Elife. 2023; 12. PMC: 10188113. DOI: 10.7554/eLife.80639. View

Li Y, Minor N, Park J, McKearin D, Maines J . Bam and Bgcn antagonize Nanos-dependent germ-line stem cell maintenance. Proc Natl Acad Sci U S A. 2009; 106(23):9304-9. PMC: 2695086. DOI: 10.1073/pnas.0901452106. View

Clarke M, Fuller M . Stem cells and cancer: two faces of eve. Cell. 2006; 124(6):1111-5. DOI: 10.1016/j.cell.2006.03.011. View

10.

Robinson M, McCarthy D, Smyth G . edgeR: a Bioconductor package for differential expression analysis of digital gene expression data. Bioinformatics. 2009; 26(1):139-40. PMC: 2796818. DOI: 10.1093/bioinformatics/btp616. View

11.

McKearin D, Spradling A . bag-of-marbles: a Drosophila gene required to initiate both male and female gametogenesis. Genes Dev. 1990; 4(12B):2242-51. DOI: 10.1101/gad.4.12b.2242. View

12.

Dobin A, Davis C, Schlesinger F, Drenkow J, Zaleski C, Jha S . STAR: ultrafast universal RNA-seq aligner. Bioinformatics. 2012; 29(1):15-21. PMC: 3530905. DOI: 10.1093/bioinformatics/bts635. View

13.

Bischof J, Maeda R, Hediger M, Karch F, Basler K . An optimized transgenesis system for Drosophila using germ-line-specific phiC31 integrases. Proc Natl Acad Sci U S A. 2007; 104(9):3312-7. PMC: 1805588. DOI: 10.1073/pnas.0611511104. View

14.

Li H, Handsaker B, Wysoker A, Fennell T, Ruan J, Homer N . The Sequence Alignment/Map format and SAMtools. Bioinformatics. 2009; 25(16):2078-9. PMC: 2723002. DOI: 10.1093/bioinformatics/btp352. View

15.

Bolstad B, Irizarry R, Astrand M, Speed T . A comparison of normalization methods for high density oligonucleotide array data based on variance and bias. Bioinformatics. 2003; 19(2):185-93. DOI: 10.1093/bioinformatics/19.2.185. View

16.

Shan L, Wu C, Chen D, Hou L, Li X, Wang L . Regulators of alternative polyadenylation operate at the transition from mitosis to meiosis. J Genet Genomics. 2017; 44(2):95-106. DOI: 10.1016/j.jgg.2016.12.007. View

17.

Jenkins V, Larkin A, Thurmond J . Using FlyBase: A Database of Drosophila Genes and Genetics. Methods Mol Biol. 2022; 2540:1-34. DOI: 10.1007/978-1-0716-2541-5_1. View

18.

Malik S, Jang W, Kim J, Kim C . Mechanisms ensuring robust repression of the Drosophila female germline stem cell maintenance factor Nanos via posttranscriptional regulation. FASEB J. 2020; 34(9):11421-11430. DOI: 10.1096/fj.202000656R. View

19.

Gonczy P, Matunis E, DiNardo S . bag-of-marbles and benign gonial cell neoplasm act in the germline to restrict proliferation during Drosophila spermatogenesis. Development. 1997; 124(21):4361-71. DOI: 10.1242/dev.124.21.4361. View

20.

Gilboa L, Lehmann R . Repression of primordial germ cell differentiation parallels germ line stem cell maintenance. Curr Biol. 2004; 14(11):981-6. DOI: 10.1016/j.cub.2004.05.049. View