How an individual cell can give rise to progeny with distinct patterns of gene expression and phenotypes, without any change in its DNA sequence, is still one of the major unsolved questions in developmental biology. Despite different epigenetic, transcriptional and post-transcriptional regulatory mechanisms have been described in a tissue and cell-specific manner, it still remains unknown how such a level of complexity can be achieved. In terms of post-transcriptional regulation, microRNAs have been proposed as key elements in the last years due to their essential role in animal survival and embryonic development. However, unlike transcription factors, whether these molecules are involved in the proper development and/or function of organs remains unclear. The pharynx of C. elegans is to date the only organ in which the lineage of every one of its cells is known. This rhythmically pumping organ, proposed as functional homolog of the heart, has been a powerful system to study organogenesis. Although, some genetic pathways that control the morphogenesis or cell fate specification in this organ have already been elucidated, there are still many open questions. One of the shared genetic networks between the pharynx and the vertebrate heart includes the miRNA
mir-1. We have identified a defective pumping behavior in
mir-1 mutant animals. The animals display higher pump and inter-peak interval (IPI) duration and consequently, a lower pumping frequency, when compared to wild type worms. We therefore performed a search against different
mir-1 targets, and identified 5 members of the vha family as potential regulators of pharyngeal muscle cells development or function. The relationship between this vacuolar ATPase family and the fusogen protein EFF-1 suggest that regulation of the vha genes may impact the proper fusion and morphogenesis of muscle cells in the pharynx. Thus, our results suggest a role for
mir-1 in pharynx development that, at the same time, is essential for the proper function of this organ. By analyzing the role of conserved microRNAs in the pharynx we expect to find conserved and essential pathways in heart development.