RNA Helicase A explained

ATP-dependent RNA helicase A (RHA; also known as DHX9, LKP, and NDHI) is an enzyme that in humans is encoded by the DHX9 gene.^{[1] [2] [3]}

Function

DEAD/DEAH box helicases are proteins, and are putative RNA helicases. They are implicated in a number of cellular processes involving alteration of RNA secondary structure such as translation initiation, nuclear and mitochondrial splicing, and ribosome and spliceosome assembly. Based on their distribution patterns, some members of this family are believed to be involved in embryogenesis, spermatogenesis, and cellular growth and division. This gene encodes a DEAD box protein with RNA helicase activity. It may participate in melting of DNA:RNA hybrids, such as those that occur during transcription, and may play a role in X-linked gene expression. It contains 2 copies of a double-stranded RNA-binding domain, a DEXH core domain and an RGG box. The RNA-binding domains and RGG box influence and regulate RNA helicase activity.^[3] The DHX9 gene is located on the long arm q of chromosome 1.

Interactions

DHX9 has been shown to interact with:

• AKAP8L,^{[4] [5]}
• BRCA1,^{[6] [7]}
• DDX17 (p72)^[8]
• DDX5 (p68),
• KHDRBS1,^[9]
• MIZF,^[10]
• NXF1,^[11]
• PRMT1,^[12]
• RELA,^[13] and
• SMN1.^[14]

Further reading

• Lee CG, Hurwitz J . A new RNA helicase isolated from HeLa cells that catalytically translocates in the 3' to 5' direction . The Journal of Biological Chemistry . 267 . 7 . 4398–407 . Mar 1992 . 10.1016/S0021-9258(18)42849-9 . 1537828 . free .
• Lee CG, Zamore PD, Green MR, Hurwitz J . RNA annealing activity is intrinsically associated with U2AF . The Journal of Biological Chemistry . 268 . 18 . 13472–8 . Jun 1993 . 10.1016/S0021-9258(19)38673-9 . 7685763 . free .
• Abdelhaleem MM, Hameed S, Klassen D, Greenberg AH . Leukophysin: an RNA helicase A-related molecule identified in cytotoxic T cell granules and vesicles . Journal of Immunology . 156 . 6 . 2026–35 . Mar 1996 . 10.4049/jimmunol.156.6.2026 . 8690889 . 24465550 . free .
• Nakajima T, Uchida C, Anderson SF, Lee CG, Hurwitz J, Parvin JD, Montminy M . RNA helicase A mediates association of CBP with RNA polymerase II . Cell . 90 . 6 . 1107–12 . Sep 1997 . 9323138 . 10.1016/S0092-8674(00)80376-1 . 16819946 . free .
• Loor G, Zhang SJ, Zhang P, Toomey NL, Lee MY . Identification of DNA replication and cell cycle proteins that interact with PCNA . Nucleic Acids Research . 25 . 24 . 5041–6 . Dec 1997 . 9396813 . 147130 . 10.1093/nar/25.24.5041 .
• Lee CG, Eki T, Okumura K, da Costa Soares V, Hurwitz J . Molecular analysis of the cDNA and genomic DNA encoding mouse RNA helicase A . Genomics . 47 . 3 . 365–71 . Feb 1998 . 9480750 . 10.1006/geno.1997.5139 .
• Anderson SF, Schlegel BP, Nakajima T, Wolpin ES, Parvin JD . BRCA1 protein is linked to the RNA polymerase II holoenzyme complex via RNA helicase A . Nature Genetics . 19 . 3 . 254–6 . Jul 1998 . 9662397 . 10.1038/930 . 10953768 .
• Lee CG, da Costa Soares V, Newberger C, Manova K, Lacy E, Hurwitz J . RNA helicase A is essential for normal gastrulation . Proceedings of the National Academy of Sciences of the United States of America . 95 . 23 . 13709–13 . Nov 1998 . 9811865 . 24884 . 10.1073/pnas.95.23.13709 . 1998PNAS...9513709L . free .
• Li J, Tang H, Mullen TM, Westberg C, Reddy TR, Rose DW, Wong-Staal F . A role for RNA helicase A in post-transcriptional regulation of HIV type 1 . Proceedings of the National Academy of Sciences of the United States of America . 96 . 2 . 709–14 . Jan 1999 . 9892698 . 15201 . 10.1073/pnas.96.2.709 . 1999PNAS...96..709L . free .
• Tang H, McDonald D, Middlesworth T, Hope TJ, Wong-Staal F . The carboxyl terminus of RNA helicase A contains a bidirectional nuclear transport domain . Molecular and Cellular Biology . 19 . 5 . 3540–50 . May 1999 . 10207077 . 84146 . 10.1128/mcb.19.5.3540.
• Westberg C, Yang JP, Tang H, Reddy TR, Wong-Staal F . A novel shuttle protein binds to RNA helicase A and activates the retroviral constitutive transport element . The Journal of Biological Chemistry . 275 . 28 . 21396–401 . Jul 2000 . 10748171 . 10.1074/jbc.M909887199 . free .
• Tang H, Wong-Staal F . Specific interaction between RNA helicase A and Tap, two cellular proteins that bind to the constitutive transport element of type D retrovirus . The Journal of Biological Chemistry . 275 . 42 . 32694–700 . Oct 2000 . 10924507 . 10.1074/jbc.M003933200 . free .
• Lee CG, Eki T, Okumura K, Nogami M, Soares Vda C, Murakami Y, Hanaoka F, Hurwitz J . The human RNA helicase A (DDX9) gene maps to the prostate cancer susceptibility locus at chromosome band 1q25 and its pseudogene (DDX9P) to 13q22, respectively . Somatic Cell and Molecular Genetics . 25 . 1 . 33–9 . Jan 1999 . 10925702 . 10.1023/B:SCAM.0000007138.44216.3a . 29684315 .
• Reddy TR, Tang H, Xu W, Wong-Staal F . Sam68, RNA helicase A and Tap cooperate in the post-transcriptional regulation of human immunodeficiency virus and type D retroviral mRNA . Oncogene . 19 . 32 . 3570–5 . Jul 2000 . 10951562 . 10.1038/sj.onc.1203676 . free .
• Pellizzoni L, Charroux B, Rappsilber J, Mann M, Dreyfuss G . A functional interaction between the survival motor neuron complex and RNA polymerase II . The Journal of Cell Biology . 152 . 1 . 75–85 . Jan 2001 . 11149922 . 2193649 . 10.1083/jcb.152.1.75 .
• Takasaki Y, Kogure T, Takeuchi K, Kaneda K, Yano T, Hirokawa K, Hirose S, Shirai T, Hashimoto H . Reactivity of anti-proliferating cell nuclear antigen (PCNA) murine monoclonal antibodies and human autoantibodies to the PCNA multiprotein complexes involved in cell proliferation . Journal of Immunology . 166 . 7 . 4780–7 . Apr 2001 . 11254741 . 10.4049/jimmunol.166.7.4780 . free .
• Yang JP, Tang H, Reddy TR, Wong-Staal F . Mapping the functional domains of HAP95, a protein that binds RNA helicase A and activates the constitutive transport element of type D retroviruses . The Journal of Biological Chemistry . 276 . 33 . 30694–700 . Aug 2001 . 11402034 . 10.1074/jbc.M102809200 . free .
• Aratani S, Fujii R, Oishi T, Fujita H, Amano T, Ohshima T, Hagiwara M, Fukamizu A, Nakajima T . Dual roles of RNA helicase A in CREB-dependent transcription . Molecular and Cellular Biology . 21 . 14 . 4460–9 . Jul 2001 . 11416126 . 87106 . 10.1128/MCB.21.14.4460-4469.2001 .

Notes and References

1. Lee CG, Hurwitz J . Human RNA helicase A is homologous to the maleless protein of Drosophila . The Journal of Biological Chemistry . 268 . 22 . 16822–30 . Aug 1993 . 10.1016/S0021-9258(19)85490-X . 8344961 . free .
2. Zhang S, Grosse F . Domain structure of human nuclear DNA helicase II (RNA helicase A) . The Journal of Biological Chemistry . 272 . 17 . 11487–94 . Apr 1997 . 9111062 . 10.1074/jbc.272.17.11487 . free .
3. Web site: Entrez Gene: DHX9 DEAH (Asp-Glu-Ala-His) box polypeptide 9.
4. Yang JP, Tang H, Reddy TR, Wong-Staal F . Mapping the functional domains of HAP95, a protein that binds RNA helicase A and activates the constitutive transport element of type D retroviruses . The Journal of Biological Chemistry . 276 . 33 . 30694–700 . Aug 2001 . 11402034 . 10.1074/jbc.M102809200 . free .
5. Westberg C, Yang JP, Tang H, Reddy TR, Wong-Staal F . A novel shuttle protein binds to RNA helicase A and activates the retroviral constitutive transport element . The Journal of Biological Chemistry . 275 . 28 . 21396–401 . Jul 2000 . 10748171 . 10.1074/jbc.M909887199 . free .
6. Schlegel BP, Starita LM, Parvin JD . Overexpression of a protein fragment of RNA helicase A causes inhibition of endogenous BRCA1 function and defects in ploidy and cytokinesis in mammary epithelial cells . Oncogene . 22 . 7 . 983–91 . Feb 2003 . 12592385 . 10.1038/sj.onc.1206195 . 8036061 .
7. Anderson SF, Schlegel BP, Nakajima T, Wolpin ES, Parvin JD . BRCA1 protein is linked to the RNA polymerase II holoenzyme complex via RNA helicase A . Nature Genetics . 19 . 3 . 254–6 . Jul 1998 . 9662397 . 10.1038/930 . 10953768 .
8. Wilson BJ, Giguère V . Identification of novel pathway partners of p68 and p72 RNA helicases through Oncomine meta-analysis . BMC Genomics . 8 . 419 . November 2007 . 18005418 . 3225811 . 10.1186/1471-2164-8-419 . free .
9. Reddy TR, Tang H, Xu W, Wong-Staal F . Sam68, RNA helicase A and Tap cooperate in the post-transcriptional regulation of human immunodeficiency virus and type D retroviral mRNA . Oncogene . 19 . 32 . 3570–5 . Jul 2000 . 10951562 . 10.1038/sj.onc.1203676 . free .
10. Fujita H, Fujii R, Aratani S, Amano T, Fukamizu A, Nakajima T . Antithetic effects of MBD2a on gene regulation . Molecular and Cellular Biology . 23 . 8 . 2645–57 . Apr 2003 . 12665568 . 152551 . 10.1128/mcb.23.8.2645-2657.2003.
11. Tang H, Wong-Staal F . Specific interaction between RNA helicase A and Tap, two cellular proteins that bind to the constitutive transport element of type D retrovirus . The Journal of Biological Chemistry . 275 . 42 . 32694–700 . Oct 2000 . 10924507 . 10.1074/jbc.M003933200 . free .
12. Smith WA, Schurter BT, Wong-Staal F, David M . Arginine methylation of RNA helicase a determines its subcellular localization . The Journal of Biological Chemistry . 279 . 22 . 22795–8 . May 2004 . 15084609 . 10.1074/jbc.C300512200 . free .
13. Tetsuka T, Uranishi H, Sanda T, Asamitsu K, Yang JP, Wong-Staal F, Okamoto T . RNA helicase A interacts with nuclear factor kappaB p65 and functions as a transcriptional coactivator . European Journal of Biochemistry . 271 . 18 . 3741–51 . Sep 2004 . 15355351 . 10.1111/j.1432-1033.2004.04314.x . free .
14. Pellizzoni L, Charroux B, Rappsilber J, Mann M, Dreyfuss G . A functional interaction between the survival motor neuron complex and RNA polymerase II . The Journal of Cell Biology . 152 . 1 . 75–85 . Jan 2001 . 11149922 . 2193649 . 10.1083/jcb.152.1.75.