Abstracts (poster) - Wissenschaft Online

Ruxandra Farcas, Eberhard Schneider, Ulrich Zechner, Achim Tresch, Hans Zischler,
Angelika Daser, Thomas Haaf
Comparison of human and non-human primate methylation
status of CpG islands in the promoter region of CCRK
Little is known about how the human brain differs from that of our closest relatives,
although it is known that humans and primates share a high extent of DNA sequence
homology. One explanation are species differences in regulation of gene expression.
Here we focused our attention on differences in promoter DNA methylation in human
and non-human primate brains. For comparative methylation analysis, we performed
bisulphite sequencing of DNA from frontal cortex of 11 humans, one chimpanzee, two
baboons, and one rhesus monkey. Species-specific methylation patterns were found for
the cell-cycle related kinase (CCRK) gene that activates CDK2 and is indispensable for
cell growth. CCRK has an intermediate CpG promoter with tendency to high-CpG
promoter. In the analyzed CpG island, we could distinguish three different regions, two
whose methylation status is conserved and one with differences in the methylation
status between the analyzed species. The first region, an ALU-Sg repeat, was almost
completely methylated in all human and primate samples. The second region, a block of
6 CpGs at the end of the ALU-Sg repeat, was mostly unmethylated in the 11 humans
and rhesus monkey, but highly methylated in chimpanzee and the two baboons. The
third region, corresponding to the end of the CpG island, was completely unmethylated
in all human and primate samples. We conclude that methylation status of the second
region varies between human and rhesus monkey on the one hand and chimpanzee and
baboon on the other hand. In future investigations, we will focus on relating our findings
to gene expression data of CCRK in primate brain.
contact:
Ruxandra Farcas
Johannes Gutenberg University
Institute for Human Genetics
farcas@humgen.klinik.uni-mainz.de
Langenbeckstraße 1
55101 Mainz (Germany)