title: Dynein light chain 1 functions in somatic cyst cells regulate spermatogonial divisions in Drosophila.
abstract: Stem cell progeny often undergo transit amplifying divisions before differentiation. In Drosophila, a spermatogonial precursor divides four times within an enclosure formed by two somatic-origin cyst cells, before differentiating into spermatocytes. Although germline and cyst cell-intrinsic factors are known to regulate these divisions, the mechanistic details are unclear. Here, we show that loss of dynein-light-chain-1 (DDLC1/LC8) in the cyst cells eliminates bag-of-marbles (bam) expression in spermatogonia, causing gonial cell hyperplasia in Drosophila testis. The phenotype is dominantly enhanced by Dhc64C (cytoplasmic Dynein) and didum (Myosin V) loss-of-function alleles. Loss of DDLC1 or Myosin V in the cyst cells also affects their differentiation. Furthermore, cyst cell-specific loss of ddlc1 disrupts Armadillo, DE-cadherin and Integrin-βPS localizations in the cyst. Together, these results suggest that Dynein and Myosin V activities, and independent DDLC1 functions in the cyst cells organize the somatic microenvironment that regulates spermatogonial proliferation and differentiation.
authors.affiliation: Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India.
authors.forename: Prakash
authors.initials: P
authors.lastname: Joti
authors.forename: Anindya
authors.initials: A
authors.lastname: Ghosh-Roy
authors.forename: Krishanu
authors.initials: K
authors.lastname: Ray
mesh_terms: D000483:Alleles; D000818:Animals; D002448:Cell Adhesion; D002454:Cell Differentiation; D049109:Cell Proliferation; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000502:physiology*; D004398:Dyneins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D019012:Integrin beta1 / Q000378:metabolism; D008297:Male; D009154:Mutation; D024701:Myosin Type V / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D013093:Spermatogonia / Q000502:physiology*; D013737:Testis / Q000502:physiology; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D000099193:rab11 GTP-Binding Proteins
chemical_list: D029721:Drosophila Proteins; D004398:Dyneins; D019012:Integrin beta1; D024701:Myosin Type V; D020691:rab GTP-Binding Proteins; C091674:bam protein, Drosophila; C542608:ctp protein, Drosophila; C116040:didum protein, Drosophila; C559123:Rab11 protein, Drosophila; D000099193:rab11 GTP-Binding Proteins