Behavior of interchromatin granules during the cell cycle

Area of Science:

• Cell Biology
• Molecular Biology
• Cytogenetics

Background:

• Interchromatin granules (IGs) are nuclear structures observed during the interphase of the cell cycle.
• Their precise role and behavior during mitosis have remained largely unclear.

Purpose of the Study:

• To investigate the ultrastructural behavior of interchromatin granules (IGs) during both interphase and mitosis.
• To determine if IGs persist throughout the entire cell cycle.

Main Methods:

• Utilized cytochemical and immunocytological approaches at the ultrastructural level.
• Examined HEp-2 and Ehrlich tumor cells.
• Employed serial section analysis, silver staining, EDTA staining, and immunogold labeling for polyadenylate nucleotidyl transferase.

Main Results:

• Identical IG behavior was observed in both cell types.
• IGs form distinct clusters in interphase nuclei, associated with coiled and fibrillar bodies.
• During mitosis, IG clusters disperse into the cytoplasm and reform within daughter nuclei after chromosome decondensation.

Conclusions:

• Interchromatin granules (IGs) are stable structures that persist throughout the entire cell cycle.
• IGs are consistently associated with RNA, as indicated by polyadenylate nucleotidyl transferase labeling.
• The dynamic behavior of IGs during mitosis suggests a role in nuclear reformation.