Due to the requirement of huge amount of starting material, it has been difficult for establishing a ChIP assay for small tissues to detect an association of a protein with transcription factors in vivo. I have recently developed a ChIP assay for transcription factors (Sry and Sox9) that utilizes chromatin from 20 intact embryonic testes (16-18 ts stage) without cross-linking protein to DNA. All ChIP assays published so far utilize cross-linking procedure to retain protein-DNA complex throughout the procedure. Question is “Is it possible to hold your protein-DNA complex for days without perturbing its binding?”.  I say yes. My experimental conditions retained that complex. Let’s see if this ChIP assay for transcription factors (Sry and Sox9) can be validated and standardized for several other transcription factors. At the end, there will be a way out for catching up mechanisms underlying early embryonic development.

The Cerebellin 4 Precursor Gene Is a Direct Target of SRY and SOX9 in Mice
Bradford ST, Hiramatsu R, Maddugoda MP, Bernard P, Chaboissier MC, Sinclair A, Schedl A, Harley V, Kanai Y, Koopman P, Wilhelm D.
Biol Reprod. 2009 Feb 11. [Epub ahead of print]

In most mammals, the expression of SRY (sex-determining region on the Y chromosome) initiates the development of testes and thus determines the sex of the individual. However, despite the pivotal role of SRY, its mechanism of action remains elusive. One important missing piece of the puzzle is the identification of genes regulated by SRY. In this study we used chromatin immunoprecipitation to identify direct SRY target genes. Anti-mouse SRY antibody precipitated a region 7.5 kb upstream of the transcriptional start site of cerebellin 4 precursor (Cbln4), which encodes a secreted protein. Cbln4 is expressed in Sertoli cells in the developing gonad with a profile mimicking that of the testis-determining gene Sox9 SRY-box containing gene 9). In transgenic XY mouse embryos with reduced Sox9 xpression, Cbln4 expression also was reduced, whereas over-expression of Sox9 in XX mice caused an up-regulation of Cbln4 expression. Finally, ectopic up-regulation of SRY in vivo resulted in ectopic expression of Cbln4. Our findings suggest that both SRY and SOX9 contribute to the male-specific up-regulation of Cbln4 in the developing testis, and identified a direct in vivo target gene of SRY.

Article link: http://www.ncbi.nlm.nih.gov/pubmed/19211811?

Symposium website

Photogallery 2006

With Drs. Eva Eicher and Roger V. Short.

Dr. Skinner keeps his lab running in a very friendly atmosphere. Science is our passion and friendship is our relation.Here is the picture of our team- half the members are absent in the picture, though.

We look forward to getting supports to education and research.

Transgenerational epigenetic effects include all processes that have evolved to achieve the nongenetic determination of phenotype. There has been a long-standing interest in this area from evolutionary biologists, who refer to it as non-Mendelian inheritance. Transgenerational epigenetic effects include both the physiological and behavioral (intellectual) transfer of information across generations. Although in most cases the underlying molecular mechanisms are not understood, modifications of the chromosomes that pass to the next generation through gametes are sometimes involved, which is called transgenerational epigenetic inheritance. There is a trend for those outside the field of molecular biology to assume that most cases of transgenerational epigenetic effects are the result of transgenerational epigenetic inheritance, in part because of a misunderstanding of the terms. Unfortunately, this is likely to be far from the truth.

Article link: Full Text  PDF