Journal of Biosciences

, 33:345

Differential dynamics of splicing factor SC35 during the cell cycle

Article

Abstract

Pre-mRNA splicing factors are enriched in nuclear domains termed interchromatin granule clusters or nuclear speckles. During mitosis, nuclear speckles are disassembled by metaphase and reassembled in telophase in structures termed mitotic interchromatin granules (MIGs). We analysed the dynamics of the splicing factor SC35 in interphase and mitotic cells. In HeLa cells expressing green fluorescent protein (GFP)-SC35, this was localized in speckles during interphase and dispersed in metaphase. In telophase, GFP-SC35 was highly enriched within telophase nuclei and also detected in MIGs. Fluorescence recovery after photobleaching (FRAP) experiments revealed that the mobility of GFP-SC35 was distinct in different mitotic compartments. Interestingly, the mobility of GFP-SC35 was 3-fold higher in the cytoplasm of metaphase cells compared with interphase speckles, the nucleoplasm or MIGs. Treatment of cells with inhibitors of cyclin-dependent kinases (cdks) caused changes in the organization of nuclear compartments such as nuclear speckles and nucleoli, with corresponding changes in the mobility of GFP-SC35 and GFP-fibrillarin. Our results suggest that the dynamics of SC35 are significantly influenced by the organization of the compartment in which it is localized during the cell cycle.

Keywords

Cell cycle dynamics FRAP analysis mitotic interchromatin granules splicing factor SC35 

Abbreviations used

ASF

alternate splicing factor

cdk

cyclin-dependent kinase

Clk

Cdc2-like kinase

DAPI

4′,6-diamidino-2-phenylindole

FBS

foetal bovine serum

FITC

fluorescein isothiocyanate

FRAP

fluorescence recovery after photobleaching

GFP

green fluorescent protein

GST

glutathione S-transferase

IGC

interchromatin granule cluster

IPTG

isopropyl-β-D-thiogalactopyranoside

mAb

monoclonal antibody

MIG

mitotic interchromatin granule

NAP

NOR-associated patch

NOR

nucleolar organizing region

PBS

phosphate-buffered saline

PVDF

polyvinylidene fluoride

RFI

relative fluorescence intensity

RS

serine-rich

SDS-PAGE

sodium dodecyl sulphate-polyacrylamide gel electrophoresis

snRNP

small nuclear ribonucleoprotein

snoRNA

small nucleolar RNA

SRPK 1

serine/arginine-rich protein kinase 1

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Copyright information

© Indian Academy of Sciences 2008

Authors and Affiliations

  1. 1.Centre for Cellular and Molecular BiologyHyderabadIndia

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