Summary of terms used
| Term . | Meaning . | Explanation . | Reference . |
|---|---|---|---|
| MSCI | Meiotic sex chromosome inactivation | Transcriptional silencing of the X and Y chromosomes that takes place during the pachytene sub-stage of male meiosis. MSCI is MSUC affecting the X and Y. | (McKee and Handel, 1993) |
| MSUC | Meiotic silencing of unsynapsed chromatin | Transcriptional silencing of unsynapsed autosomal segments that takes place during the pachytene sub-stage of male and female meiosis. | (Schimenti, 2005) |
| MSUD | Meiotic silencing by unpaired DNA | Transcriptional silencing of genes by virtue of their homology to other genes that are themselves unpaired during meiosis. | (Shiu et al., 2001) |
| PMSC | Post-meiotic sex chromatin | The heterochromatic, transcriptionally repressed conformation of the X and Y chromosomes during spermiogenesis. | (Namekawa et al., 2006) |
| PSCR | Post-meiotic sex chromosome repression | Transcriptional repression of the X and Y chromosomes during spermiogenesis. | (Turner et al., 2006) |
| XCI | X chromosome inactivation | Silencing of one of the two X chromosomes that takes place early in female mammalian pre-implantation development. | (Heard and Disteche, 2006) |
| BRCA1 | Breast cancer 1, early onset | Tumour suppressor protein linked to a wide variety of processes, including DNA DSB repair, cell cycle progression and MSCI/MSUC. | (Boulton, 2006) |
| ATR | Ataxia telangiectasia and Rad3-related | Member of the PI3 kinase-like kinase family. Involved in DNA DSB repair, cell cycle progression and MSCI/MSUC. | (Traven and Heierhorst, 2005) |
| γH2AX | Phosphorylated histone H2AX | Modification carried out by the PI3 kinase-like kinases and involved in the early stages of DNA DSB repair-mainly via recruitment of MDC1. Also functions in MSCI/MSUC. | (Fillingham et al., 2006) |
| MDC1 | Mediator of DNA damage checkpoint 1 | DNA-repair protein that interacts with γH2AX at the sites of DNA DSBs. Loss of MDC1 results in impaired recruitment of DNA DSB-repair factors (e.g. ATM to DNA DSBs) and chromosome instability. | (Stucki et al., 2005) |
| uH2A | Ubiquitylated histone H2A | Modification carried out by the concerted efforts of E1 (activating), E2(conjugating) and E3 (ligating) enzymes and involved in transcriptional silencing both in the context of somatic XCI and MSCI/MSUC. | (Baarends et al., 2005) |
| UBE2A/B | Ubiquitin-conjugating enzyme E2A/B, RAD6 homolog | Enzymes involved in the second step of histone ubiquitylation - conjugation. Both are candidates for the generation of uH2A during MSCI/MSUC. | (Baarends et al., 2005) |
| Suv39h2 | Suppressor of variegation 3-9 homolog 2 | Histone methyltransferase that acts with Suv39h1 to regulate histone H3 K9 dimethylation at pericentric heterochromatin. Suv39h1/2 double mutants are sterile, but sex body-associated H3K9Me2 and MSCI are unaffected. | (Peters et al., 2001) |
| H2AFY | H2A histone family, member Y | Large H2A variant implicated in somatic XCI and MSCI/MSUC. May exert function via inhibition of PARP-1 activity. | (Hoyer-Fender et al., 2000)(Ouararhni et al., 2006) |
| H2AZ | H2A histone family, member Z | Histone variant implicated in chromosome segregation and heterochromatin formation. May also function in PSCR. | (Greaves et al., 2006) |
| CBX1, CBX3 | Chromobox homolog 1, 3 | Chromobox-containing `adaptor' proteins that bind specific post-translational histone modifications and recruit effectors of gene silencing. | (Motzkus et al., 1999)(Metzler-Guillemain et al.,2003) |
| Term . | Meaning . | Explanation . | Reference . |
|---|---|---|---|
| MSCI | Meiotic sex chromosome inactivation | Transcriptional silencing of the X and Y chromosomes that takes place during the pachytene sub-stage of male meiosis. MSCI is MSUC affecting the X and Y. | (McKee and Handel, 1993) |
| MSUC | Meiotic silencing of unsynapsed chromatin | Transcriptional silencing of unsynapsed autosomal segments that takes place during the pachytene sub-stage of male and female meiosis. | (Schimenti, 2005) |
| MSUD | Meiotic silencing by unpaired DNA | Transcriptional silencing of genes by virtue of their homology to other genes that are themselves unpaired during meiosis. | (Shiu et al., 2001) |
| PMSC | Post-meiotic sex chromatin | The heterochromatic, transcriptionally repressed conformation of the X and Y chromosomes during spermiogenesis. | (Namekawa et al., 2006) |
| PSCR | Post-meiotic sex chromosome repression | Transcriptional repression of the X and Y chromosomes during spermiogenesis. | (Turner et al., 2006) |
| XCI | X chromosome inactivation | Silencing of one of the two X chromosomes that takes place early in female mammalian pre-implantation development. | (Heard and Disteche, 2006) |
| BRCA1 | Breast cancer 1, early onset | Tumour suppressor protein linked to a wide variety of processes, including DNA DSB repair, cell cycle progression and MSCI/MSUC. | (Boulton, 2006) |
| ATR | Ataxia telangiectasia and Rad3-related | Member of the PI3 kinase-like kinase family. Involved in DNA DSB repair, cell cycle progression and MSCI/MSUC. | (Traven and Heierhorst, 2005) |
| γH2AX | Phosphorylated histone H2AX | Modification carried out by the PI3 kinase-like kinases and involved in the early stages of DNA DSB repair-mainly via recruitment of MDC1. Also functions in MSCI/MSUC. | (Fillingham et al., 2006) |
| MDC1 | Mediator of DNA damage checkpoint 1 | DNA-repair protein that interacts with γH2AX at the sites of DNA DSBs. Loss of MDC1 results in impaired recruitment of DNA DSB-repair factors (e.g. ATM to DNA DSBs) and chromosome instability. | (Stucki et al., 2005) |
| uH2A | Ubiquitylated histone H2A | Modification carried out by the concerted efforts of E1 (activating), E2(conjugating) and E3 (ligating) enzymes and involved in transcriptional silencing both in the context of somatic XCI and MSCI/MSUC. | (Baarends et al., 2005) |
| UBE2A/B | Ubiquitin-conjugating enzyme E2A/B, RAD6 homolog | Enzymes involved in the second step of histone ubiquitylation - conjugation. Both are candidates for the generation of uH2A during MSCI/MSUC. | (Baarends et al., 2005) |
| Suv39h2 | Suppressor of variegation 3-9 homolog 2 | Histone methyltransferase that acts with Suv39h1 to regulate histone H3 K9 dimethylation at pericentric heterochromatin. Suv39h1/2 double mutants are sterile, but sex body-associated H3K9Me2 and MSCI are unaffected. | (Peters et al., 2001) |
| H2AFY | H2A histone family, member Y | Large H2A variant implicated in somatic XCI and MSCI/MSUC. May exert function via inhibition of PARP-1 activity. | (Hoyer-Fender et al., 2000)(Ouararhni et al., 2006) |
| H2AZ | H2A histone family, member Z | Histone variant implicated in chromosome segregation and heterochromatin formation. May also function in PSCR. | (Greaves et al., 2006) |
| CBX1, CBX3 | Chromobox homolog 1, 3 | Chromobox-containing `adaptor' proteins that bind specific post-translational histone modifications and recruit effectors of gene silencing. | (Motzkus et al., 1999)(Metzler-Guillemain et al.,2003) |