An efficient in situ hybridization protocol for multiple tissue sections and probes on miniaturized slides

Area of Science:

• Molecular Biology
• Developmental Biology
• Genetics

Background:

• In situ hybridization is crucial for detecting gene activity in biological samples.
• Standard tissue section in situ hybridization (TSISH) often faces challenges with reproducibility and stringent conditions.
• Whole-mount in situ hybridization (WMISH) offers robust hybridization but is typically used for whole organisms or embryos.

Purpose of the Study:

• To develop an improved method for detecting gene activity in tissue sections.
• To combine the strengths of TSISH and WMISH for enhanced sensitivity and spatial resolution.
• To establish a reproducible and stringent in situ hybridization protocol for tissue sections.

Main Methods:

• A modified TSISH protocol was developed using miniature glass slides and laboratory-made containers for handling tissue sections.
• A key innovation involves using airtight reaction vessels in a dry thermostat for critical hybridization steps.
• The method was validated on serial frozen sections of murine neonatal cerebellum, hybridizing for the developmentally regulated genes math1 and neuroD.

Main Results:

• The combined TSISH-WMISH approach yielded excellent spatial resolution and a high dynamic range of signal intensity for both math1 and neuroD.
• Reproducible and stringent hybridization conditions were achieved, overcoming limitations of standard TSISH.
• The method demonstrated practicability on consecutive serial frozen sections.

Conclusions:

• The novel method effectively facilitates the detection of gene activity in tissue sections with improved accuracy and resolution.
• This technique allows for simple processing of multiple probes, efficient use of small tissue samples, and is amenable to automation.
• The approach offers a valuable tool for studying gene expression patterns in developmental biology and other fields.