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Dynamic interplay of spectrosome and centrosome organelles in asymmetric stem cell divisions.

Bang C, Cheng J - PLoS ONE (2015)

Bottom Line: Utilizing time-lapse live cell imaging, customized tracking, and image processing programs, we found that most acentrosomal GSCs have the spectrosomes reposition from the basal end (wild type) to the apical end close to hub-GSC interface (acentrosomal GSCs).For acentrosomal GSCs, their mitotic spindles were still highly oriented and divided asymmetrically with longer mitosis duration, resulting in asymmetric divisions.Moreover, when the spectrosome was knocked out, the centrosomes velocity decreased and centrosomes located closer to hub-GSC interface.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, The University of Illinois at Chicago, Chicago, Illinois, United States of America.

ABSTRACT
Stem cells have remarkable self-renewal ability and differentiation potency, which are critical for tissue repair and tissue homeostasis. Recently it has been found, in many systems (e.g. gut, neurons, and hematopoietic stem cells), that the self-renewal and differentiation balance is maintained when the stem cells divide asymmetrically. Drosophila male germline stem cells (GSCs), one of the best characterized model systems with well-defined stem cell niches, were reported to divide asymmetrically, where centrosome plays an important role. Utilizing time-lapse live cell imaging, customized tracking, and image processing programs, we found that most acentrosomal GSCs have the spectrosomes reposition from the basal end (wild type) to the apical end close to hub-GSC interface (acentrosomal GSCs). In addition, these apically positioned spectrosomes were mostly stationary while the basally positioned spectrosomes were mobile. For acentrosomal GSCs, their mitotic spindles were still highly oriented and divided asymmetrically with longer mitosis duration, resulting in asymmetric divisions. Moreover, when the spectrosome was knocked out, the centrosomes velocity decreased and centrosomes located closer to hub-GSC interface. We propose that in male GSCs, the spectrosome recruited to the apical end plays a complimentary role in ensuring proper spindle orientation when centrosome function is compromised.

No MeSH data available.


Centrosome velocity and distance to hub-GSC interface change in hts-mut GSCs.Based on the centrosome tracking analysis of live-image sequences, the A) Interphase centrosome velocities are shown for both hts-mut GSCs and wild type GSCs (p<0.01 between hts-mut and wild type for both GSC-inherited and GB-inherited centrosomes), and the B) GSC-inherited centrosome distance to the hub-GSC interphase histograms are shown for both hts-mut and wild type GSCs (p<0.01).
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pone.0123294.g005: Centrosome velocity and distance to hub-GSC interface change in hts-mut GSCs.Based on the centrosome tracking analysis of live-image sequences, the A) Interphase centrosome velocities are shown for both hts-mut GSCs and wild type GSCs (p<0.01 between hts-mut and wild type for both GSC-inherited and GB-inherited centrosomes), and the B) GSC-inherited centrosome distance to the hub-GSC interphase histograms are shown for both hts-mut and wild type GSCs (p<0.01).

Mentions: Although spectrosome knockout does not affect centrosome or spindle orientation, further analysis of dynamic migration pattern show the centrosome migration pattern does change. Our live imaging results showed that the motility of GSC-inherited centrosomes during interphase is significantly slower than that of GB-inherited centrosomes in hts-mut (p<0.01). Quantitatively, in wild type, the GSC-inherited centrosome velocity is 0.53±0.38μm/min (n = 654) while the GB-inherited velocity is 0.57±0.34μm/min (n = 639); and in hts-mut, the GSC-inherited centrosome velocity is 0.35±0.3μm/min (n = 734) and GB-inherited velocity is 0.47±0.32μm/min (n = 716) (Fig 5A). Furthermore, GSCs in hts-mut flies have both less motile GSC-inherited and GB-inherited centrosomes than that in wild type (p<0.01). Interestingly, we also found that GSC-inherited centrosomes in wild type throughout the interphase were located significantly further away from the hub-GSC interface than that in hts-mut (p<0.01) (Fig 5B). The results reveal the previously undiscovered dynamic interplay of centrosome and spectrosome.


Dynamic interplay of spectrosome and centrosome organelles in asymmetric stem cell divisions.

Bang C, Cheng J - PLoS ONE (2015)

Centrosome velocity and distance to hub-GSC interface change in hts-mut GSCs.Based on the centrosome tracking analysis of live-image sequences, the A) Interphase centrosome velocities are shown for both hts-mut GSCs and wild type GSCs (p<0.01 between hts-mut and wild type for both GSC-inherited and GB-inherited centrosomes), and the B) GSC-inherited centrosome distance to the hub-GSC interphase histograms are shown for both hts-mut and wild type GSCs (p<0.01).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4388834&req=5

pone.0123294.g005: Centrosome velocity and distance to hub-GSC interface change in hts-mut GSCs.Based on the centrosome tracking analysis of live-image sequences, the A) Interphase centrosome velocities are shown for both hts-mut GSCs and wild type GSCs (p<0.01 between hts-mut and wild type for both GSC-inherited and GB-inherited centrosomes), and the B) GSC-inherited centrosome distance to the hub-GSC interphase histograms are shown for both hts-mut and wild type GSCs (p<0.01).
Mentions: Although spectrosome knockout does not affect centrosome or spindle orientation, further analysis of dynamic migration pattern show the centrosome migration pattern does change. Our live imaging results showed that the motility of GSC-inherited centrosomes during interphase is significantly slower than that of GB-inherited centrosomes in hts-mut (p<0.01). Quantitatively, in wild type, the GSC-inherited centrosome velocity is 0.53±0.38μm/min (n = 654) while the GB-inherited velocity is 0.57±0.34μm/min (n = 639); and in hts-mut, the GSC-inherited centrosome velocity is 0.35±0.3μm/min (n = 734) and GB-inherited velocity is 0.47±0.32μm/min (n = 716) (Fig 5A). Furthermore, GSCs in hts-mut flies have both less motile GSC-inherited and GB-inherited centrosomes than that in wild type (p<0.01). Interestingly, we also found that GSC-inherited centrosomes in wild type throughout the interphase were located significantly further away from the hub-GSC interface than that in hts-mut (p<0.01) (Fig 5B). The results reveal the previously undiscovered dynamic interplay of centrosome and spectrosome.

Bottom Line: Utilizing time-lapse live cell imaging, customized tracking, and image processing programs, we found that most acentrosomal GSCs have the spectrosomes reposition from the basal end (wild type) to the apical end close to hub-GSC interface (acentrosomal GSCs).For acentrosomal GSCs, their mitotic spindles were still highly oriented and divided asymmetrically with longer mitosis duration, resulting in asymmetric divisions.Moreover, when the spectrosome was knocked out, the centrosomes velocity decreased and centrosomes located closer to hub-GSC interface.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, The University of Illinois at Chicago, Chicago, Illinois, United States of America.

ABSTRACT
Stem cells have remarkable self-renewal ability and differentiation potency, which are critical for tissue repair and tissue homeostasis. Recently it has been found, in many systems (e.g. gut, neurons, and hematopoietic stem cells), that the self-renewal and differentiation balance is maintained when the stem cells divide asymmetrically. Drosophila male germline stem cells (GSCs), one of the best characterized model systems with well-defined stem cell niches, were reported to divide asymmetrically, where centrosome plays an important role. Utilizing time-lapse live cell imaging, customized tracking, and image processing programs, we found that most acentrosomal GSCs have the spectrosomes reposition from the basal end (wild type) to the apical end close to hub-GSC interface (acentrosomal GSCs). In addition, these apically positioned spectrosomes were mostly stationary while the basally positioned spectrosomes were mobile. For acentrosomal GSCs, their mitotic spindles were still highly oriented and divided asymmetrically with longer mitosis duration, resulting in asymmetric divisions. Moreover, when the spectrosome was knocked out, the centrosomes velocity decreased and centrosomes located closer to hub-GSC interface. We propose that in male GSCs, the spectrosome recruited to the apical end plays a complimentary role in ensuring proper spindle orientation when centrosome function is compromised.

No MeSH data available.