M31 and macroH2A1.2 colocalise at the pseudoautosomal region during mouse meiosis.
Progression through meiotic prophase is associated with dramatic changes in chromosome condensation. Two proteins that have been implicated in effecting these changes are the mammalian HP1-like protein M31 (HP1beta or MOD1) and the unusual core histone macroH2A1.2. Previous analyses of M31 and macroH2A1.2 localisation in mouse testis sections have indicated that both proteins are components of meiotic centromeric heterochromatin and of the sex body, the transcriptionally inactive domain of the X and Y chromosomes. This second observation has raised the possibility that these proteins co-operate in meiotic sex chromosome inactivation. In order to investigate the roles of M31 and macroH2A1.2 in meiosis in greater detail, we have examined their localisation patterns in surface-spread meiocytes from male and female mice. Using this approach, we report that, in addition to their previous described staining patterns, both proteins localise to a focus within the portion of the pseudoautosomal region (PAR) that contains the steroid sulphatase (Sts) gene. In light of the timing of its appearance and of its behaviour in sex-chromosomally variant mice, we suggest a role for this heterochromatin focus in preventing complete desynapsis of the terminally associated X and Y chromosomes prior to anaphase I.
Turner
J M
JM
Laboratory of Developmental Genetics, National Institute for Medical Research, Mill Hill London, NW7 1AA, UK.
Burgoyne
P S
PS
Singh
P B
PB
D000818:Animals; D001192:Arylsulfatases / Q000235:genetics; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D023902:Chromosome Pairing / Q000235:genetics / Q000502:physiology; D005260:Female; D006570:Heterochromatin / Q000737:chemistry / Q000378:metabolism*; D006657:Histones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008540:Meiosis / Q000502:physiology; D051379:Mice; D009865:Oocytes / Q000166:cytology*; D020161:Physical Chromosome Mapping; D011418:Prophase / Q000235:genetics / Q000502:physiology; D012730:Sex Chromosomes / Q000502:physiology; D013094:Spermatozoa / Q000166:cytology*; D043266:Steryl-Sulfatase
C096188:Cbx1 protein, mouse; D002868:Chromosomal Proteins, Non-Histone; D006570:Heterochromatin; D006657:Histones; C120756:macroH2A histone; D001192:Arylsulfatases; D043266:Steryl-Sulfatase