Understanding signed quantities and its arithmetic is one of the challenging topics of middle school mathematics. The "specialized content knowledge" (SCK) for teaching integers includes understanding of a variety of representations that may be used while teaching. In this study, we argue that meanings of integers and integer operations form the foundation for the construction of SCK about representations used to teach integers. We report that teachers' concerns about teaching the topic of integers implicate issues of meaning, although this may not always be explicitly acknowledged by teachers. We develop a framework of integer meanings synthesizing previous research, and describe how the framework allowed teachers to investigate a wide range of representations including contexts and thereby construct SCK in a professional development setting. Teachers constructed SCK by connecting various meanings of integers with one another and with representations including contexts. Teachers made two important shifts, from exclusively using the state meaning of integers to including the application of change meaning to representations and from exclusive use of formal models to including contexts to teach integer addition and subtraction. An implication of the study is that frameworks of meaning for key mathematical topics could be an important component of pre- and in-service teacher education.