The first LOTUS domain in Oskar and Tudor-containing proteins 5 and 7
The first LOTUS domain in Oskar and Tudor-containing proteins 5 and 7: The LOTUS containing proteins are germline-specific and are found in the nuage/polar granules of germ cells. Tudor-containing protein 5 and 7 belong to the evolutionary conserved Tudor domain-containing protein (TDRD) family involved in germ cell development. In mice, TDRD5 and TDRD7 are components of the intermitochondrial cements (IMCs) and the chromatoid bodies (CBs), which are cytoplasmic ribonucleoprotein granules involved in RNA processing for spermatogenesis. Oskar protein is a critical component of the pole plasm in the Drosophila oocyte, which is required for germ cell formation.The exact molecular function of LOTUS domain remains to be identified. Its occurrence in proteins associated with RNA metabolism suggests that it might be involved in RNA binding function. The presence of several basic residues and RNA fold recognition motifs support this hypothesis. The RNA binding function might be the first step of regulating mRNA translation or localization.