March 3 journal club

Matt from the Evans lab will be presenting. This is the plug he gave me (is it just me, or does this sound like one of the guys who writes the weekly plugs for the JHSPH happy hour?) --

"For this week I'm actually going to present a combination of two papers. Now, before you get irritated that you have to read two papers, hear me out. First off, they aren't too long. And secondly, they are really good and important papers:

The immunoglobulin superfamily protein Izumo is required for sperm to fuse with eggs (Nature, 2005)

Putative sperm fusion protein IZUMO and the role of N-glycosylation (BBRC, 2008)

Both papers were published by Masaru Okabe's group at the Genome Information Research Center at Osaka University. The main paper I'm presenting was published in Nature back in 2005, and was really influential because it gave new insight into the mechanism of sperm-egg fusion (Nature 434:234). The paper identified an IgSF family member, Izumo, as the first and only sperm protein to date shown to be completely essential for sperm-egg fusion. The second paper I will be discussing is a follow up paper published in October 2008. This paper explored the role that a conserved N-glycolsylation site played in Izumo function (BBRC 377:910). Despite the fact that Izumo is by far the most interesting molecular candidate on the sperm to mediate sperm-egg fusion, we still don't know much about how it functions. Therefore, I'll be discussing some of my work that focuses on the role that tyrosine O-sulfation, an understudied post-translational modification, may play in Izumo function.

Hopefully, you all will find the story as interesting as I do. I'll also go into the interesting history behind where Izumo got its name, how it was identified after sitting in a freezer for over 10 years, and some of the work that has gone into trying to make a vaccine using Izumo as the antigen.

Definitely take a look at the first paper from 2005, and if you have time, look over the second."

Feb. 17 journal club

Mouse differentiating spermatogonia can generate germinal stem cells in vivo
Barroca et al., Nature Cell Biology 11, 190 - 196 (2008)

Becca from the Matunis lab will be presenting. Here's what she says about the paper:

"Basically I chose this paper because it demonstrates that differentiating spermatogonia have the potential to reconstitute spermatogensis in gamma-irradiated mouse testes. It suggests that in the permissive microenvironment and with the appropriate cellular factors, differentiating spermatogonia can be re-programmed into germline stem cells.

This paper is directly relevant to my research as I am trying to understand the mechanism of dedifferentiation using Drosophila spermatogensis as a model system. Our system is especially useful because we know the precise location of the stem cell niche and have cellular markers that distinguish germline stem cells from their immediate daughters. We are also able to genetically manipulate the niche, and recently, we have developed methods to image the niche live in order to observe the cellular rearrangements that occur during dedifferentiation."