Required to regulate peristaltic movement and also for germline proliferation in males and females. Expressed in specific tissues such as the developing central nervous system (CNS) and both the male and female germline. In the CNS, it is restricted in a subset of cells during embryogenesis and early larval development. In embryos, it is also expressed in salivary glands. In the testis, expressed in somatic cyst cells throughout the distal region where the mitotic cysts develop, extending through to meiotic cysts. Expressed from stage 16 embryos. Flies have defects in locomotor behavior and die during larval development, due to abnormal neural function. Mutant males lacking functional slmo survive into adulthood and show an early division of the germline but never progress through the gonial divisions. Mutant females demonstrate germarial degeneration and reduced fertility. Belongs to the slowmo family.