The nucleus of the cell is a membrane-bound organelle that includes the nuclear envelope, nucleoli, and nuclear lamina and is the site of gene expression. Nuclear structure can be selectively visualized by staining nuclear proteins or directly staining nucleic acids. Cell-permeant nucleic acid stains make it possible to stain live cells or tissues with minimal processing to reveal the natural location of cells in tissues and provide a means to follow nuclear changes throughout cellular processes, from mitosis to apoptosis.

ReadyProbes® nuclear dyes

ReadyProbes® reagents provide the easiest fluorescent staining method for nucleic acids. Formulated for room-temperature storage, they are provided in convenient dropper bottles for ease of use. Just add two drops per milliliter of solution to stain your cells. We offer a selection of ReadyProbes® nucleic acid stains with a choice of wavelengths for multiplexing and colocalization in either live or fixed cells

NucBlue™ Live Cell Stain Enlarge image

CellLight® reagents for nuclear proteins

A choice of CellLight® reagents for labeling the nucleus allows you to label histone proteins using a histone 2B sequence (13.7 kDa) to follow the dynamics of chromosomal behavior, or localize fluorescent protein to the nucleus using an SV40 nuclear localization sequence (1.0 kDa). CellLight® proteins can be multiplexed with other fluorescent probes for analysis in live cells, or after fixation for colocalization studies. These ready-to-use constructs express fluorescent fusion proteins after a simple transfection step, and they work like cell stains with minimal toxicity or chemical disruption.

CellLight® Nucleus-CFPEnlarge image

High-performance nuclear dyes

Ideal nuclear dyes should exhibit affinity for both DNA and RNA and display enhanced fluorescence upon binding. For live-cell staining they should be permeant to eukaryotic and prokaryotic membranes and result in minimal toxicity to the cell. For fixed-cell staining, they should be stable and selective. Some of the highest-affinity DNA stains used with fixed cells are also used as dead-cell stains because they are impermeant to eukaryotic or prokaryotic cell membranes

We offer a selection of Molecular Probes® nucleic acid stains with a choice of wavelengths for multiplexing and colocalization in either live or fixed cells.

TO-PRO®-3 reagent Enlarge image

Staining the nucleolus

Nucleoli are non–membrane-bound bodies found within the nucleus and are the site where ribosomal RNA is transcribed. The SYTO® RNASelect™ Green Fluorescent Cell Stain is a cell-permeant nucleic acid stain that is selective for RNA. Although virtually nonfluorescent in the absence of nucleic acids, the SYTO® RNASelect™ stain exhibits bright green fluorescence when bound to RNA, but only a weak fluorescent signal when bound to DNA. The SYTO® RNASelect™ stain can be used to detect the nucleoli, and cells may be counterstained with a nuclear stain such as DAPI.

SYTO® RNASelect™ green-fluorescent cell stainEnlarge image

High-content screening (HCS)

Versatile HCS NuclearMask™ stains can be used to measure DNA content and perform cell demarcation with live or formaldehyde-fixed cells on high-content imaging and analysis (HCS) platforms. HCS NuclearMask™ stains are available in a choice of colors for multiplexing flexibility with other functional and structural probes to ask complex biological questions.

SYTO® RNASelect™ green-fluorescent cell stainEnlarge image
Selection guides
 
Readout
Fluorescent staining of nucleic acids
Target
 Membrane-permeable dyes targeting RNA and DNA
Membrane impermeable dye targeting RNA and DNA
 
Common filter set
DAPI
Cy®5
DAPI
Labels
Hoechst 33342
NucRed® Live
DAPI
Ex/Em (nm)
360/460
638/686
360/460
Signal-to-noise ratio
Photostability
Multiplexing
Yes
Yes
Yes
Live cells
Yes
Yes
No
Fixed cells
No
No
Yes
Fixable
Yes
No
No
Platform
Imaging 
Imaging 
Imaging 
Format
6 x dropper bottles
6 x dropper bottles
6 x dropper bottles
Cat. No.
 
Readout
 Expression of fluorescent fusion protein
Expression of fluorescent fusion protein
Target
 Labels histone proteins within the chromosome
 Localizes flruorescent protein in the nucleus
Common filter set
FITC
TRITC
DAPI
FITC
TRITC
Labels
GFP
RFP
CFP
GFP
RFP
Ex/Em (nm)
488/520
555/584
435/485
488/520
555/584
Signal-to-noise ratio
Photostability
Multiplexing
Yes
Yes
Yes
Yes
Yes
Live cells
Yes
Yes
Yes
Yes
Yes
Fixed cells
No
No
No
No
No
Fixable
Yes
Yes
Yes
Yes
Yes
Platform
 Imaging
 Imaging
Imaging 
Imaging 
 Imaging
Format
1 mL
1 mL
1 mL
1 mL
1 mL
Cat. No.
  SYTOX® Green Nucleic Acid Stain TO-PRO®-3 Iodide
Readout
Fluorescent staining of nucleic acids
Target
 Membrane-permeable dyes targeting RNA and DNA
Common filter set
FITC
TRITC
FITC
Cy®5
Labels
SYTO® 9
SYTO® 82
SYTOX® Green
TO-PRO®-3
Ex/Em (nm)
483/503
541/560
483/503
642/661
Signal-to-noise ratio
Photostability
Multiplexing
Yes
Yes
Yes
Yes
Live cells
Yes
Yes
No
No
Fixed cells
No
No
Yes
Yes
Fixable
Yes
Yes
No
No
Platform
 Imaging
Imaging 
Imaging 
Imaging 
Format
100 μL
250 μL
250 μL
1 mL
Cat. No.
 
Readout
 Fluorescent staining
Target
 Selective for RNA
Common filter set
FITC
Labels
SYTO® RNASelect™
Ex/Em (nm)
490/530
Signal-to-noise ratio
Photostability
Multiplexing
Yes
Live cells
No
Fixed cells
Yes
Fixable
Yes
Platform
Imaging 
Format
100 μL
Cat. No.
 
Readout
Stains nucleus for demarcation
Common filter set
DAPI
Texas Red®
Cy®5
Ex/Em (nm)
350⁄451
622⁄645
638⁄686
Signal-to-noise ratio
Photostability
Multiplexing
Yes
Yes
Yes
Live cells
Yes
Yes
Yes
Fixed cells
Yes
Yes
No
Fixable
Yes
Yes
Yes
Platform
HCS 
HCS 
HCS 
Format
65 µL
125 µL
400 µL
Cat. No.
For Research Use Only. Not for use in diagnostic procedures.