Analysis of the Role of Akirin Interactions with Nuclear Body Proteins During Myogenesis

Akirin is a highly conserved, small nuclear protein of indeterminate structure ubiquitously expressed in non-fungal eukaryotic species. It was first discovered in the innate immune response, but many other functions have since been found, including embryonic muscle patterning and myogenesis. Animals with either nonfunctional or missing Akirin have aberrations in embryonic muscle patterning, along with other defects. Akirin interacts with transcription factors such as Twist to coordinate development through interfacing between Twist and other complexes, such as the Brahma Chromatin Remodeling Complex (BRM). Therefore, Akirin likely plays a general role in transcription during early development, interfacing with other transcriptional machinery such as nuclear bodies. Nuclear bodies are non-membrane-bound organelles found in the nucleus that concentrate and package transcriptional and splicing machinery, specifically the Cajal Body (CB) and Histone Locus Body (HLB). Through Drosophila embryo immunostaining for myosin heavy chain and green fluorescent protein, interactions between Akirin and Mute, a component of the HLB, as well as interactions between Akirin and Coilin, a component of both the CB and the HLB, were observed. Using polytene chromosome squashes and anti-Akirin immunostaining of a coilin-eYFP Drosophila line, co-localization of Akirin and Coilin was revealed, implying a physical interaction. These results shed light on the complex process of transcription in the embryo, opening new paths to study developmental disorders and congenital defects