The Input Signal Step Function (ISSF), a standard method to encode input signals in SBML models with software...

Area of Science:

• Computational biology
• Chronobiology
• Systems biology

Background:

• Computational models of circadian rhythms require accurate time-dependent inputs, such as light-dark cycles.
• Current Systems Biology Markup Language (SBML) models often lack standardized methods for encoding these inputs, hindering reproducibility and model reuse.
• Existing methods for representing time-dependent inputs in SBML are inconsistent, complicating the integration and comparison of different models.

Discussion:

• The Input Signal Step Function (ISSF) provides a numerically continuous and configurable method for encoding periodic and transient inputs in SBML.
• ISSF is broadly applicable to various experimental manipulations, including light-dark cycles, drug treatments, and temperature changes.
• The function's flexibility allows for the reproduction of diverse waveforms, enhancing the utility of computational models.

Key Insights:

• ISSF enables standard simulation software to accurately reproduce specialized circadian protocols, such as phase-response curves.
• Implementation of ISSF in SBML facilitates the modification of existing models to match published results, thereby improving reproducibility.
• A user-friendly software tool has been developed to configure ISSF without requiring specialized SBML knowledge, promoting wider adoption.

Outlook:

• Establishing a community-standard approach for representing entraining inputs in circadian clock models is crucial for advancing chronobiology research.
• Standardization through ISSF can accelerate the development and validation of computational models across different research groups.
• Widespread adoption of ISSF will foster greater collaboration and facilitate the sharing of standardized, reusable circadian clock models.