Histone chaperone (composed of Spt16 and Pob3) which facilitates RNA polymerase transcription. Also found at replication forks and associated with replication proteins and may facilitate replication through chromatin



Spt16=Cdc68=Ssf1; Pob3

Molecular weight

ScPob3 63 kDa;  ScSpt16 119 kDa


Biochemical properties

•Histone disruption 2a/2b displacement (1)


•Spt16 has histone acetyl transferase motifs (no detectable activity) (2) (3)

Protein interactions


•Pob interacts Pol alpha (2) (4)

•FACT interacts nek (5) involved in g1/s transition

•Both found associated with GINS complex (6)

•Pob3 interacts RPA (7)

•Mcm2-7 complex (8) (via mcm4) suggest stimulates mcm activity on nucleosome substrates.

•Spt16 interacts with nuA3 (acetylates h3) (9)



•FACT interacts  dcdp (HAT) (10)





 •pob (7)


Cellular location and expression


•binds at origins (8)



Other comments


•Likely role in transcription as well as replication (11) -probably more important in genes with structured not random nuclerosome arrangements (12) suggested to unload histones in front of transcription complex and load them back on again after (13)

• Fact mutants are sensitive to hu but this can be overcome by disrupting the set2 (h3k36) or the chd1 ( chromatin remodeller) genes (14)


•FACT binding to chromatin regulated by poly adp ribosylation (15)

•Monoub H2B needs FACT (16)

•Suggested to be involved in phosphorylation p53 on DNA damage (17)

Revised by


Last edited

14 July 09



1.    Orphanides,G., Wu,W.H., Lane,W.S., Hampsey,M. and Reinberg,D. (1999) The chromatin-specific transcription elongation factor FACT comprises human SPT16 and SSRP1 proteins. Nature 400, 284-288.

2.    Wittmeyer,J., Joss,L. and Formosa,T. (1999) Spt16 and Pob3 of Saccharomyces cerevisiae form an essential, abundant heterodimer that is nuclear, chromatin-associated, and copurifies with DNA polymerase alpha. Biochemistry 38, 8961-8971.

3.    Belotserkovskaya,R., Oh,S., Bondarenko,V.A., Orphanides,G., Studitsky,V.M. and Reinberg,D. (2003) FACT facilitates transcription-dependent nucleosome alteration. Science 301, 1090-1093.

4.    Wittmeyer,J. and Formosa,T. (1997) The Saccharomyces cerevisiae DNA polymerase alpha catalytic subunit interacts with Cdc68/Spt16 and with Pob3, a protein similar to an HMG1-like protein. Mol Cell Biol 17, 4178-4190.

5.    Tan,B.C. and Lee,S.C. (2004) Nek9, a novel FACT-associated protein, modulates interphase progression. J Biol Chem 279, 9321-9330.

6.    Gambus,A., Jones,R.C., Sanchez-Diaz,A., Kanemaki,M., van Deursen,F., Edmondson,R.D. and Labib,K. (2006) GINS maintains association of Cdc45 with MCM in replisome progression complexes at eukaryotic DNA replication forks. Nat Cell Biol 8, 358-366.

7.    VanDemark,A.P., Blanksma,M., Ferris,E., Heroux,A., Hill,C.P. and Formosa,T. (2006) The structure of the yFACT Pob3-M domain, its interaction with the DNA replication factor RPA, and a potential role in nucleosome deposition. Mol Cell 22, 363-374.

8.    Tan,B.C., Chien,C.T., Hirose,S. and Lee,S.C. (2006) Functional cooperation between FACT and MCM helicase facilitates initiation of chromatin DNA replication. EMBO J 25, 3975-3985.

9.    John,S., Howe,L., Tafrov,S.T., Grant,P.A., Sternglanz,R. and Workman,J.L. (2000) The something about silencing protein, Sas3, is the catalytic subunit of NuA3, a yTAF(II)30-containing HAT complex that interacts with the Spt16 subunit of the yeast CP (Cdc68/Pob3)-FACT complex. Genes Dev 14, 1196-1208.

10.  Newman,B.L., Lundblad,J.R., Chen,Y. and Smolik,S.M. (2002) A Drosophila homologue of Sir2 modifies position-effect variegation but does not affect life span. Genetics 162, 1675-1685.

11.  Schlesinger,M.B. and Formosa,T. (2000) POB3 is required for both transcription and replication in the yeast Saccharomyces cerevisiae. Genetics 155, 1593-1606.

12.  Jimeno-Gonzalez,S., Gomez-Herreros,F., Alepuz,P.M. and Chavez,S. (2006) A gene-specific requirement for FACT during transcription is related to the chromatin organization of the transcribed region. Mol Cell Biol 26, 8710-8721.

13.  Formosa,T., Ruone,S., Adams,M.D., Olsen,A.E., Eriksson,P., Yu,Y., Rhoades,A.R., Kaufman,P.D. and Stillman,D.J. (2002) Defects in SPT16 or POB3 (yFACT) in Saccharomyces cerevisiae cause dependence on the Hir/Hpc pathway: polymerase passage may degrade chromatin structure. Genetics 162, 1557-1571.

14.  Biswas,D., Takahata,S., Xin,H., Dutta-Biswas,R., Yu,Y., Formosa,T. and Stillman,D.J. (2008) A role for Chd1 and Set2 in negatively regulating DNA replication in Saccharomyces cerevisiae. Genetics 178, 649-659.

15.  Huang,J.Y., Chen,W.H., Chang,Y.L., Wang,H.T., Chuang,W.T. and Lee,S.C. (2006) Modulation of nucleosome-binding activity of FACT by poly(ADP-ribosyl)ation. Nucleic Acids Res 34, 2398-2407.

16.  Pavri,R., Zhu,B., Li,G., Trojer,P., Mandal,S., Shilatifard,A. and Reinberg,D. (2006) Histone H2B monoubiquitination functions cooperatively with FACT to regulate elongation by RNA polymerase II. Cell 125, 703-717.

17.  Keller,D.M., Zeng,X., Wang,Y., Zhang,Q.H., Kapoor,M., Shu,H., Goodman,R., Lozano,G., Zhao,Y. and Lu,H. (2001) A DNA damage-induced p53 serine 392 kinase complex contains CK2, hSpt16, and SSRP1. Mol Cell 7, 283-292.