Likewise, individuals suffering from Huntington's disease exhibit clock-regulated disruption of neuroendocrine output, and of the sleep-wake cycles [ 43- 45].
Since there was no candidate for the transcriptional regulator whose expression level was up- or down-regulated upon disruption of mutS, mutL, or mutS2 gene (data not shown), it can be speculated that a constitutively expressed transcriptional regulator is responsible for the regulation of the vitamin B1-dependent ROS-detoxifying system upon inactivation of DNA repair enzymes.
An opposite effect is observed for anterior Hox genes, which are up-regulated by disruption of Cdx function (Fig. 5a c).
In contrast, clusters 1, 2, 9, and 10 are up- or down-regulated by disruption of any of the three Cdx genes, albeit more strongly by Cdx4 disruption.
For example, genes in clusters 6 and 8 are strongly up-regulated by disruption of Cdx4 function, but not at all are affected by Cdx1 or Cdx2 disruption.
At the other end of the Hoxa cluster, Hoxa1 and Hoxa2, the most anteriorly-expressed Hox genes in the embryo, respond in the opposite direction, being up-regulated by disruption of Cdx gene function (Fig. 5a, b).
We found that Cdx4 regulates genes from all four Hox clusters, including a major effect on posterior Hox genes which are strikingly down-regulated by disruption of Cdx4 function (Fig. 5a).
It is more likely that SnoN is transcriptionally down-regulated due to disruption of the negative feedback loop involving TGFβ signalling [ 7].
Similarly, TTHA0989 (66-fold), TTHA0994 (2,042-fold 2,042-fold (177-fold), and mosTTHA0995 genes from TTHA0980 to TTHA0987 (>20-fold) were significantly down-regulated by the disruption of the Argonaute gene, as was the case with the RNase HI gene disruptant.
Disruption of Cdx2 function down-regulated Smad4.2 expression, while disruption of Cdx4 function up-regulated Smad4.1 (Fig. 5g).
In a later study, Kadener et al. [ 66] found that abrogation of microRNA biogenesis led to both a marked rise in circadian-regulated gene expression and a disruption of circadian-regulated behavioral rhythms, thus indicating a role for microRNA in clock timing.
