Component of the FACT complex, a general chromatin factor that acts to reorganize nucleosomes. The FACT complex is involved in multiple processes that require DNA as a template such as mRNA elongation, DNA replication and DNA repair. During transcription elongation the FACT complex acts as a histone chaperone that both destabilizes and restores nucleosomal structure. It facilitates the passage of RNA polymerase II and transcription by promoting the dissociation of one histone H2A-H2B dimer from the nucleosome, then subsequently promotes the reestablishment of the nucleosome following the passage of RNA polymerase II (By similarity). In embryos, promotes cell cycle progression and chromosomal segregation (PubMed:25446273, PubMed:30336114). Plays a role in the development of the anterior pharynx during embryonic development (PubMed:30336114). Component of the FACT complex, a stable heterodimer of spt-16 and hmg-3 or hmg-4. Expressed in the germline and somatic cells. Expressed throughout development (PubMed:30336114). First expressed in embryos at the 1-cell stage (PubMed:30336114). RNAi-mediated knockdown in embryos results in failed hatching in 83% of animals (PubMed:30336114). In addition, these embryos lack the anterior pharynx (PubMed:30336114). RNAi-mediated knockdown at the L4 larval stage results in failed development of the anterior pharynx (PubMed:30336114). RNAi-mediated knockdown at this stage results in defective cell cycle initiation, duration and completion in embryos, and abnormalities in chromosome segregation (PubMed:25446273, PubMed:30336114). Belongs to the peptidase M24 family. SPT16 subfamily. Although related to the peptidase M24 family, this protein lacks conserved active site residues suggesting that it may lack peptidase activity.