With five Pc proteins (CBX2, CBX4, CBX6, CBX7 and CBX8), six Psc proteins (BMI1, MEL18, MBLR, NSPC1, RNF159 and RNF3), three Ph proteins (HPH1, HPH2 and HPH3) and two Sce proteins (RING1 and RING2) there is enormous scope for combinatorial diversity [10], [11].
In Drosophila, PRC1 is composed of stoichiometric amounts of Polycomb (Pc), Posterior sex combs (Psc), Polyhomeotic (Ph), and Sex combs extra (Sce) proteins; however, because mammalian genomes encode five Pc, six Psc, three Ph, and two Sce orthologs, there are many possible combinations of PRC1 components (summarized in Figure 2A) (Whitcomb et al., 2007).
Expansion of the PcG genes has led to a more complicated picture in mammalian cells in which there are five Pc (CBX2, CBX4, CBX6, CBX7 and CBX8), six Psc (MEL18, BMI1, MBLR, RNF159, NSPC1 and RNF3), three Ph (HPH1, HPH2 and HPH3) and two Sce (RING1 and RING2) orthologues (Gil and Peters, 2006; Whitcomb et al, 2007).
Of the three, SCE most directly relates to systems that specifically target spatial cognition.
This allowed for a measurement of anaerobic (AOD) and aerobic (VO2) energy contributions throughout the four SCE repetitions [24].
Cronbach's Alpha for the sum of all four SCE domains was 0.77.
The sample size was calculated for a 15% difference of the total score of all four SCE domains.
However, following treatment with 6 µM MMC, Rad21+/− MEFs showed a modest increase in SCE frequency with an average of five SCEs per metaphase spread (Fig. 1D).
In contrast, the frequency of SCEs in WT MEFs was elevated substantially to an average of fourteen SCEs per metaphase spread, significantly higher (p <0.0001) than that of Rad21+/− MEFs (Fig. 1D).
c) Reliability and SEM of eight SCEs sat in 2008 and 2009, in eight different medical specialties.
Previous studies reported the isolation and characterization of two mutant Sce alleles (Breen and Duncan, 1986; Fritsch et al., 2003; Gaytán de Ayala Alonso et al., 2007; Gorfinkiel et al., 2004).
