Table A. Thirteen previously reported mouse genes that are expressed in spermatogonia but not in somatic tissues Gene Mage Ube1y Usp9y Rbmy Tuba3/Tuba7 Stra8 Ott Sycp2 Sycp1 Figla Sycp3 Ddx4 Dazl Expression Testis Testis Testis Testis Testis Testis Testis and ovary Testis and ovary Testis and ovary Testis and ovary Testis and ovary Testis and ovary Testis and ovary Chromosome X Y Y Y 6 6 X 2 3 6 10 13 17 References 31 32 33 8 34 35 36 37 38 39 40 41 6,7 Supplementary references and notes 31. De Plaen, E. et al. A new family of mouse genes homologous to the human MAGE genes. Genomics 55, 176-184 (1999). 32. Mitchell, M.J., Woods, D.R., Tucker, P.K., Opp, J.S. & Bishop, C.E. Homology of a candidate spermatogenic gene from the mouse Y chromosome to the ubiquitinactivating enzyme E1. Nature 354, 483-486 (1991). 33. Brown, G.M. et al. Characterisation of the coding sequence and fine mapping of the human DFFRY gene and comparative expression analysis and mapping to the Sxrb interval of the mouse Y chromosome of the Dffry gene. Hum. Mol. Genet. 7, 97-107 (1998). 34. Villasante, A. et al. Six mouse alpha-tubulin mRNAs encode five distinct isotypes: testis-specific expression of two sister genes. Mol. Cell. Biol. 6, 2409-2419 (1986). 35. Oulad-Abdelghani, M. et al. Characterization of a premeiotic germ cell-specific cytoplasmic protein encoded by Stra8, a novel retinoic acid-responsive gene. J. Cell Biol. 135, 469-477 (1996). 36. Kerr, S.M., Taggart, M.H., Lee, M. & Cooke, H.J. Ott, a mouse X-linked multigene family expressed specifically during meiosis. Hum. Mol. Genet. 5, 1139-1148 (1996). 37. Offenberg, H.H. et al. SCP2: a major protein component of the axial elements of synaptonemal complexes of the rat. Nucleic Acids Res. 26, 2572-2579 (1998). 38. Sage, J. et al. The Sycp1 loci of the mouse genome: successive retropositions of a meiotic gene during the recent evolution of the genus. Genomics 44, 118-126 (1997). 39. Liang, L., Soyal, S.M. & Dean, J. FIGalpha, a germ cell specific transcription factor involved in the coordinate expression of the zona pellucida genes. Development 124, 4939-4947 (1997). 40. Klink, A., Lee, M. & Cooke, H.J. The mouse synaptosomal complex protein gene Sycp3 maps to band C of chromosome 10. Mamm. Genome 8, 376-377 (1997). 41. Fujiwara, Y. et al. Isolation of a DEAD-family protein gene that encodes a murine homolog of Drosophila vasa and its specific expression in germ cell lineage. Proc. Natl. Acad. Sci. USA 91, 12258-12262 (1994). 42. We have also identified putative X-linked human orthologs of the other three novel X-linked mouse genes: Tktl1, Tex16, and Pramel3. The human TKTL1 gene was previously discovered and shown to be expressed in many somatic tissues [J. F. Coy et al., Genomics 32, 309 (1996)]; we found that the gene is abundantly transcribed in testes (not shown). We identified human X-linked sequences (Genbank Z95126) homologous to mouse Tex16 but observed no expression (as judged by RT-PCR) in any of the eight human tissues listed in Fig. 3; the human ortholog may be a pseudogene. We identified human X-linked sequences (Genbank Z70226) homologous to mousePramel3 but have not characterized the human gene's expression or cDNA sequence. The search for human orthologs of the remaining seven novel autosomal mouse genes (Pramel1, Tex17, Rnh2, Tex18, Piwil2, Tex20, Tex19) is complicated by the existence of multiple related sequences in the human genome and/or the inavailability of corresponding human genomic sequence. . 43. Lawson, D.M. et al. Solving the structure of human H ferritin by genetically engineering intermolecular crystal contacts. Nature 349, 541-544 (1991). 44. Baker, R.T., Tobias, J.W. & Varshavsky, A. Ubiquitin-specific proteases of Saccharomyces cerevisiae. Cloning of UBP2 and UBP3, and functional analysis of the UBP gene family. J. Biol. Chem. 267, 23364-23375 (1992). 45. Coy, J.F. et al. Molecular cloning of tissue-specific transcripts of a transketolaserelated gene: implications for the evolution of new vertebrate genes. Genomics 32, 309-316 (1996). 46. Chiang, C.M. & Roeder, R.G. Cloning of an intrinsic human TFIID subunit that interacts with multiple transcriptional activators. Science 267, 531-536 (1995). 47. van Baren, N. et al. PRAME, a gene encoding an antigen recognized on a human melanoma by cytolytic T cells, is expressed in acute leukaemia cells. Br. J. Haematol. 102, 1376-1379 (1998). 48. Segref, A. et al. Mex67p, a novel factor for nuclear mRNA export, binds to both poly(A)+ RNA and nuclear pores. Embo J. 16, 3256-3271 (1997). 49. Gruter, P. et al. TAP, the human homolog of Mex67p, mediates CTE-dependent RNA export from the nucleus. Mol. Cell 1, 649-659 (1998). 50. Kang, Y. & Cullen, B.R. The human Tap protein is a nuclear mRNA export factor that contains novel RNA-binding and nucleocytoplasmic transport sequences. Genes Dev. 13, 1126-1139 (1999). 51. Herold, A. et al. TAP (NXF1) belongs to a multigene family of putative RNA export factors with a conserved modular architecture. Mol. Cell. Biol. 20, 8996-9008. (2000). 52. Hanks, S.K. & Quinn, A.M. Protein kinase catalytic domain sequence database: identification of conserved features of primary structure and classification of family members. Methods Enzymol. 200, 38-62 (1991). 53. Ponting, C.P. Tudor domains in proteins that interact with RNA. Trends Biochem. Sci. 22, 51-52 (1997). 54. Kobe, B. & Deisenhofer, J. The leucine-rich repeat: a versatile binding motif. Trends Biochem. Sci. 19, 415-421 (1994). 55. Mouse Rnf17 appears to encode a protein of 626 residues. A mouse cDNA sequence corresponding to the 5' portion of Rnf17 was reported recently; it appeared to encode a protein of 316 residues [X. Y. Yin, K. Gupta, W. P. Han, E. S. Levitan, E. V. Prochownik, Oncogene 18, 6621 (1999)]. The discrepancy may be the result of alternative splicing or sequencing errors near the 3' end of the previously reported cDNA sequence (compare GenBank AF190166 [1098 nucleotides; 951 nucleotide open reading frame] with GenBank AF285585 [2094 nucleotides; 1881 nucleotide open reading frame]). Yin and colleagues demonstrated that the portion of the protein encoded by their partial cDNA interacted with mad proteins in vitro. In the case of human RNF17, alternative splicing appears to generate two protein isoforms. . 56. Cox, D.N. et al. A novel class of evolutionarily conserved genes defined by piwi are essential for stem cell self-renewal. Genes Dev. 12, 3715-3727 (1998). 57. Schmidt, A. et al. Genetic and molecular characterization of sting, a gene involved in crystal formation and meiotic drive in the male germ line of Drosophila melanogaster. Genetics 151, 749-760 (1999). 58. Mooslehner, K., Muller, U., Karls, U., Hamann, L. & Harbers, K. Structure and expression of a gene encoding a putative GTP-binding protein identified by provirus integration in a transgenic mouse strain. Mol. Cell. Biol. 11, 886-893 (1991).