Capillary morphogenesis gene (CMG)-1 is among the genes differentially expressed in mouse male germ line stem cells and embryonic stem cells.
We recently established a technique to expand male germ line stem (GS) cells in long-term culture without losing their spermatogenic capacity. To gain insight into the genetic program of these cells, we compared the mRNA expression profile of GS cells with that of embryonic stem (ES) cells using DNA microarrays. We found 79 genes that were upregulated in GS cells compared to ES cells, including synaptonemal complex protein-1, deleted in azoospermia-like, ubiquitin-conjugating enzyme E2B, and ubiquitin carboxy-terminal hydrolase L1, all of which are functionally important for spermatogenesis. In addition, we identified a cDNA encoding the mouse ortholog of capillary morphogenesis gene (CMG)-1. CMG-1 transcripts were predominantly produced in spermatogonia and spermatocytes in mouse testis. When CMG-1 expression was attenuated in a mouse spermatocyte-derived cell line, GC-2spd(ts), by a target-specific short interfering RNA, the morphology of the cells was changed and the expression of cyclin D2 was abrogated. A reporter assay using a genomic region upstream of the mouse cyclin D2 gene revealed that this downmodulation occurs at the transcriptional level. We detected FLAG-tagged CMG-1 protein in the nuclei of transfected COS7 cells, suggesting that CMG-1 may play a unique role in the transcriptional regulation of the cyclin D2 gene. The upregulated GS genes identified in this study will provide useful information for the future investigation of spermatogonial stem cells and the early phase of male germ cell differentiation.
Fujino
Ryu-Suke
RS
Stem cell project group, The Tokyo Metropolitan Institute of Medical Science, Tokyo Metropolitan Organization for Medical Research, Tokyo, Japan.
Ishikawa
Yu-Ichiro
Y
Tanaka
Kiyoko
K
Kanatsu-Shinohara
Mito
M
Tamura
Kazuhiro
K
Kogo
Hiroshi
H
Shinohara
Takashi
T
Hara
Takahiko
T
D000818:Animals; D002460:Cell Line; D056742:Cyclin D2; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D005854:Germ Cells / Q000166:cytology / Q000502:physiology*; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D013090:Spermatocytes / Q000166:cytology / Q000502:physiology; D013093:Spermatogonia / Q000166:cytology / Q000502:physiology; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*
C518363:CMG-1 protein, mouse; C486196:Ccnd2 protein, mouse; D056742:Cyclin D2; D016213:Cyclins; D003598:Cytoskeletal Proteins; C490080:IFT74 protein, human; D034741:RNA, Small Interfering