Downloaded from www.microbiologyresearch.org by IP: 54.70.40.11 On: Mon, 10 Dec 2018 22:34:18 Journal of General Virology (2000), 81, 1009–1015. Printed in Great Britain ................................................................................................................................................................................................................................................................................... Human papillomavirus type 16 E7-regulated genes : regulation of S100P and ADP/ATP carrier protein genes identified by differential-display technology Bolette Hellung Schønning, 1 Maja Be  vort, 2 Sanne Mikkelsen, 1 Mia Andresen, 1 Peter Thomsen, 1 Henrik Leffers 2 and Bodil Norrild 1 1 Institute of Molecular Pathology, Protein Laboratory, Panum Institute, Blegdamsvej 3C, Bldg 6.2, DK-2200 Copenhagen N, Denmark 2 Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark Human papillomavirus type 16 (HPV-16) is the dominant risk factor for the development of cervical cancer. The virus encodes three oncoproteins, of which the E7 oncoprotein is the major protein involved in cell immortalization and transformation. E7 is a multi-functional protein. It binds the retinoblastoma tumour-suppressor protein (pRb), which regulates progression through the G 1 restriction point in the cell cycle. The E7 protein interacts with transcription-regulatory proteins such as the TATA box-binding protein and with proteins of the AP1 transcription factor family. To identify additional proteins regulated by E7, differential-display PCR was used to identify differentially expressed mRNAs in cells containing an inducible E7 protein. It is reported that E7 expression leads to regulation of the genes encoding the calcium-binding protein S100P and the mitochondrial ADP/ATP carrier protein. These data identify new functions of the E7 protein and thus expand the number of routes by which HPV-16 influences cell growth control, although the function of S100P has still to be elucidated. Introduction Human papillomavirus type 16 (HPV-16) is an oncogenic DNA virus that encodes six early and two late proteins, where the two early proteins E6 and E7 are major oncoproteins. They disturb the control of the cell cycle by their interaction with cellular proteins that are important for progression through the G  restriction point. Both the E6 and E7 proteins are necessary for immortalization of human keratinocytes (Mu  nger et al., 1989 ; Hawley-Nelson et al., 1989). However, both E6 and E7 alone are able to transform primary rodent cells in collaboration with activated Ras (Phelps et al., 1988 ; Storey & Banks, 1993). The E6 protein binds to and degrades the p53 tumour- suppressor protein through a ubiquitin-dependent pathway and, thus, interferes with both cell cycle control and the apoptotic pathway (Scheffner et al., 1990, 1993). The E7 protein exhibits multiple functions, such as protein–protein interactions with retinoblastoma protein (pRb), other pocket proteins and the cyclin-dependent kinase cdk2 (Dyson et al., Author for correspondence : Bodil Norrild. Fax 45 35 36 01 16. e-mail bonobiobase.dk 1989, 1992 ; Tommasino et al., 1993) and with proteins regulating transcription, such as the TATA box-binding protein (TBP) (Massimi et al., 1996 ; Phillips & Vousden, 1997) and the AP1 transcription factors (Antinore et al., 1996). The E7 protein decreases the transcriptional activity of p53 (Massimi et al., 1997), although p53 accumulates in E7- expressing cells (Jones et al., 1997). E7 binding to pRb leads to the release of the transcription factor E2F (Dyson et al., 1989), which influences the expression of the genes b-myb, smooth-muscle α-actin and p14 ARF (Lam et al., 1994 ; Morris et al., 1993 ; Nishida et al., 1995 ; Bates et al., 1998). E7 also functions in a pRbE2F-independent manner, as E7 mutants are defective in binding pRb but retain immortalizing potential in primary human keratinocytes (Edmonds & Vousden, 1989). Mutations in the N-terminal end, as well as in the zinc-binding cysteine motif in the C-terminal end, of the E7 protein abolished both the immortalizing and transforming properties (Jewers et al., 1992 ; Vousden, 1993). Although the E7 proteins from high-risk and low-risk HPV types are similar, they bind pRb with different affinities, and only the high risk- type E7 causes immortalization and transformation of infected 0001-6805  2000 SGM BAAJ