I participated in 5th Vertebrate Sex Determination Symposium in Kona, Hawaii from the 20th through the 24th of April, 2009. Since I flew from Pullman early in the morning, it was already 11:30 am when plane landed at Kona International Airport. Another hour was spent for catching a taxi and dropping off my luggage at the hotel. My previous mentor Dr. Yoshi Nagahama had already finished his Opening Talk, which I wanted to attend at any cost. No luck! I also missed the talk of Dr. Robin Lovell-Badge, who is the godfather of sex determination research. However, I will be able to hear this talk next month in Orofino, ID where Dr. Lovell-Badge will give a guest lecture at the CRB Retreat program of WSU&UI.
Most of the talks were on beta-catenin, Wnt4, FoxL2 and R- spondin. Non-mammalian talks were equally interesting. The molecular mechanism of differentiation of fetal and adult Leydig cells was presented by Dr. Ken Morohashi of Kysushu University, which was one of the best talks given in this meeting. My talk was well-received and the ChIP assay I developed was well-appreciated.

Meeting started at 8:30 and ended at 18:00 everyday except for 22nd afternoon. I took some pictures, which are sitting in the Picasaweb. Photo .

The group of Dr. Dagmar Wilhelm at Queensland University have found a gene that could be the potential target for Sry action during sex determination. They immunoprecipitated this fragment from E11.5 dpc gonads using anti-Sry antibody specific to mouse. The approach they have used is novel and there are other potential candidate genes in the list, which they will slowly be characterizing.

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?

Fifth international symposium on the biology of vertebrate sex determination is going to be held at Royal Kona Resort in Kona, Hawaii from April 20 through April 24, 2009. The aim of this symposium is to bring together scientists and students from a wide variety of disciplines with a common interest in sex determination. I am also participating at the meeting and the title is "Neurotrophin-3, a target gene for Sry action". I anticipate meeting with renown scientists in the field. So far, in each symposium, scientists have presented at least one breakthrough in the field. I am anxiously waiting to hear another yet new breakthrough  on Sry/Sox9 signalling in the gonad. For details of this and previous meetings, please visit the following website:

Symposium website

Photogallery 2006

With Drs. Eva Eicher and Roger V. Short.