For the past three years, the Transmedia Research Group at the Department of Semiotics, University of Tartu, has been developing open access online materials for supporting the teaching of humanities-related subjects in Estonian- and Russian-language secondary schools. This paper maps the theoretical and conceptual starting points of these materials. The overarching goal of the educational platforms is to support cultural coherence and autocommunication by cultivating literacies necessary for holding meaningful dialogues with cultural heritage. To achieve the goal, the authors have been seeking ways of purposeful harnessing of transmedial, crossmedial and other tools offered by the contemporary digital communication space. We have started with an understanding of culture as education - a model which is grounded in cultural semiotics and highlights the role of cultural experience and cultural self-description in learning literacies. From these premises we proceed to explicating the value of a transdisciplinary pedagogy for methodical translation of the theoretical concepts into practical solutions in teaching and learning culture.