Component of the Integrator complex, a complex involved in the transcription of small nuclear RNAs (snRNA) and their 3'-box-dependent processing (PubMed:23097424). Involved in the 3'-end processing of the U7 snRNA, and also the spliceosomal snRNAs U1 and U5 (PubMed:23097424). Plays a role as a regulator of spermatogenesis (PubMed:19357193). Crucial regulator of the mitotic cell cycle and development (PubMed:15737938, PubMed:19357193). Required for the correct dynein-dynactin perinuclear localization important for nucleus-centrosome coupling that occur upon meiotic progression of primary spermatocytes (PubMed:19357193,PubMed:23904267). Plays a role in sperm motility and fertility (PubMed:19357193). May have a role in the PNG/PLU/GNU pathway (PubMed:15737938). Belongs to the multiprotein complex Integrator, at least composed of IntS1, IntS2, IntS3, IntS4, omd/IntS5, IntS6, defl/IntS7, IntS8, IntS9, IntS10, IntS11, IntS12, asun/IntS13 and IntS14. Colocalizes with dynein-dynactin on the nuclear surface at the meiotic G2/prophase transition in primary spermatocytes (PubMed:19357193). Nuclear location is required for recruitment of dynein motors to nuclear envelope at G2/M (PubMed:23904267). Expressed in nurse cells at stages 9-10 of oogenesis and exported to the oocyte. Also expressed in the follicle cells surrounding the oocyte. Expressed both maternally and zygotically. Expressed in the nucleus during the G2 phase of primary spermatocytes at stages S3-S4. Distributed between the nucleus and the cytoplasm in G2 phase of primary spermatocytes at stage S5. Localized in the cytoplasm in G2 phase of primary spermatocytes at stage S6. Remains dispersed throughout the cell until the completion of meiosis when it becomes restricted from nuclei of onion-stage spermatides. Phosphorylated. Results in almost complete steril males. Mature sperm formed in small amounts in testes are immotile or weakly motile; seminal vesicles are largely empty. Primary spermatocytes appeared normal (Cysts of 16 cells); however, spermatids show irregularities in nuclear size and number. Spermatocytes I exhibit failure of nucleus-centrosome coupling that normally occur upon meiotic phase entry; those that progress through meiotic divisions exhibit defects in spindle assembly and chromosome segregation. When injected into Xenopus embryos, causes developmental arrest with gastrulation defects and defective cell cycles resulting in polyploid nuclei. RNAi injection into HeLa cells or Drosophila syncytial embryos causes mitotic cell cycle, giving rise to multinucleated polyploidy cells. Belongs to the asunder family. Truncated C-terminus.