发信人: assasin (冷血---何时能被加热？), 信区: Biology
标 题: MCBJC, cellular neurobiology, Mar. 10, 2
发信站: The unknown SPACE (Tue Mar 11 23:09:10 2003) WWW-POST

MCBJC, cellular neurobiology, Mar. 10, 2003, by Assasin

***I decide to volunteer to make a presentation for the delayed and missed
MCBJC for this week. hope the folks who agreed to participate MCBJC take their
duty and keep it running.***




paper:

Shen K. and Bargmann C. I. (2003) The immunoglobulin superfamily protein SYG-1
determines the location of specific synapses in C. elegans. Cell 112, 619-630.

Comments:

This is a good paper on synaptogenesis during C. elegans development.
Synaptogenesis has been extensively studied in mouse and fly neuromuscular
junction. And it has enriched our understanding on the molecular and cellular
mechanism of synaptogenesis. Instead studying synaptogenesis in C. elegans is
kind of new. This paper addressed an almost untouched fundamental
question in cellular neurobiology, that is how a specific synaptic site is
chosen from many potential contacting sites a neuron’s axon makes.
The authors indentified an Ig superfamily protein, SYG-1, as a candidate
receptor for synaptic specificity. What’s surprising is that the signal for
SYG-1 is not from the post-synaptic partner, the VC neurons. Instead, it’s
coming from the neighboring vulval epithelial cells. So it seemed that the
pre- and post-synaptic apparatus for constructing the synapse are not the
factors responsible for specifying where the synapse is going to form. The
factor is from the epithelial cell onto which the axon branch does not form
synaptic button. The results suggest the following model of synaptogenesis in
C. elegans.

Guide post signal
1 1
1 1
1 1
V 1
Receptor on axon (SYG-1) 1
1 1 ??
1 1
1 1
V 1
Pre-synaptic vesicle clustering 1
1 1
1 ?? 1
1 1
V V
Post-synaptic differentiation
1
1
1
V
Synapse formation

Questions:
1). What’s unique about the methods the authors used to study synaptic site
specification?

2). Why C. elegans is a good organism to address synaptic specificity issue?

3). In the syg-1 mutant, the synaptic vesicles are just displaced a little bit
anterior. Why weren’t they transported to the very anterior termini where the
HSN neuron synapses on other targets?

4). A problem about the paper is that they couldn’t characterize well the
SYG-1 expression pattern. So, in the functional study, they express syg-1::gfp
transgene under unc-86 promoter which is much stronger than the syg-1
promoter. So it’s an overexpression experiment. What flaws could this cause
to the explanation of SYG-1’s function?




--
※ 修改:·assasin 於 Mar 11 23:09:10 修改本文·[FROM: 136.152.]
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 136.152.]
发信人: assasin (冷血---何时能被加热？), 信区: Biology
标 题: Re: MCBJC, cellular neurobiology, Mar. 10, 2
发信站: The unknown SPACE (Tue Mar 11 22:33:01 2003) WWW-POST

Shen Kang is a faculty candidate and have got offer(s) from
Harvard/Stanford/Berkeley (which school, I don't know). His work is novel and
opened a big area.

I hope every member of the JC at least read the paper pasted every week. And
participate in the discussion if you feel it does help you to forge your
scientific thinking. And the one who is supposed to present take his/her duty.

---Assasin


【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: MCBJC, cellular neurobiology, Mar. 10, 2003, by Assasin
:
: ***I decide to volunteer to make a presentation for the delayed and missed
: MCBJC for this week. hope the folks who agreed to participate MCBJC take
their
: duty and keep it running.***
:
:
:
:
: paper:
:
: Shen K. and Bargmann C. I. (2003) The immunoglobulin superfamily protein
SYG-1
: determines the location of specific synapses in C. elegans. Cell 112,
619-630.
:
: Comments:
:
: This is a good paper on synaptogenesis during C. elegans development.
: Synaptogenesis has been extensively studied in mouse and fly neuromuscular
: junction. And it has enriched our understanding on the molecular and
cellular
: mechanism of synaptogenesis. Instead studying synaptogenesis in C. elegans
is
: kind of new. So this paper sort of addressed an almost untouched fundamental
: question in cellular neurobiology, that is how a specific synaptic site is
: chosen from many potential contacting sites a neuron’s axon makes.
: The authors indentified an Ig superfamily protein, SYG-1, as a candidate
: receptor for synaptic specificity. What’s surprising is that the signal for
: SYG-1 is not from the post-synaptic partner, the vm2 muscle. Instead, it’s
: coming from the neighboring vulval epithelial cell(s). So it seemed that the
: pre- and post-synaptic apparatus for constructing the synapse is are the
: factors responsible for specifying where the synapse is going to form. The
: factor is from the epithelial cell onto which the axon branch does not form
: synaptic button. The results suggest the following model of synaptogenesis
in
: C. elegans.
:
: Guide post signal
: 1 1
: 1 1
: 1 1
: V 1
: Receptor on axon (SYG-1) 1
: 1 1 ??
: 1 1
: 1 1
: V 1
: Pre-synaptic vesicle clustering 1
: 1 1
: 1 ?? 1
: 1 1
: V V
: Post-synaptic differentiation
: 1


--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 136.152.]
发信人: oil (brother), 信区: Biology
标 题: Re: MCBJC, cellular neurobiology, Mar. 1
发信站: The unknown SPACE (Tue Mar 11 23:04:04 2003) WWW-POST


i feel the jump might be big for most of us here
i have a general puzzle: why bother to study worm?
for beauty, for understanding, for cancer, etc
the reason isn't strong enough to me now by somehow

【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: Shen Kang is a faculty candidate and have got offer(s) from
: Harvard/Stanford/Berkeley (which school, I don't know). His work is novel
and
: opened a big area.
:
: I hope every member of the JC at least read the paper pasted every week. And
: participate in the discussion if you feel it does help you to forge your
: scientific thinking. And the one who is supposed to present take his/her
duty.
:
: ---Assasin
:
:
: 【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: : MCBJC, cellular neurobiology, Mar. 10, 2003, by Assasin
: :
: : ***I decide to volunteer to make a presentation for the delayed and missed
: : MCBJC for this week. hope the folks who agreed to participate MCBJC take
: their
: : duty and keep it running.***
: :
: :
: :
: :
: : paper:
: :
: : Shen K. and Bargmann C. I. (2003) The immunoglobulin superfamily protein
: SYG-1
: : determines the location of specific synapses in C. elegans. Cell 112,
: 619-630.
: :
: : Comments:
: :
: : This is a good paper on synaptogenesis during C. elegans development.
: : Synaptogenesis has been extensively studied in mouse and fly neuromuscular
: : junction. And it has enriched our understanding on the molecular and
: cellular
: : mechanism of synaptogenesis. Instead studying synaptogenesis in C. elegans
: is
: : kind of new. So this paper sort of addressed an almost untouched
fundamental
: : question in cellular neurobiology, that is how a specific synaptic site is
: : chosen from many potential contacting sites a neuron’s axon makes.
: : The authors indentified an Ig superfamily protein, SYG-1, as a candidate
: : receptor for synaptic specificity. What’s surprising is that the signal
for
: : SYG-1 is not from the post-synaptic partner, the vm2 muscle. Instead, it’
s
: : coming from the neighboring vulval epithelial cell(s). So it seemed that
the
: : pre- and post-synaptic apparatus for constructing the synapse is are the
: : factors responsible for specifying where the synapse is going to form. The
: : factor is from the epithelial cell onto which the axon branch does not
form
: : synaptic button. The results suggest the following model of synaptogenesis
: in
: : C. elegans.


--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 128.125.]
发信人: assasin (冷血---何时能被加热？), 信区: Biology
标 题: Re: MCBJC, cellular neurobiology, Mar. 1
发信站: The unknown SPACE (Tue Mar 11 23:21:13 2003) WWW-POST

Mechanisms of many biological phenomena like development, carcinogenesis and
heritable diseases of across the metazoan (from lower organism worm to fly,
zebrafish, mice, human) turned out to be highly conserved. However, to
cahracterized new genes responsible for these processes in humans, it's hard.
Based on the assumption that these mechanisms should be conserved between worm
and human, which are largely true in many cases, people take advantage of worm
genetics to quickly identify these genes. And then, find the homologue in
higher organisms. This approach really speed up the researches not only on
human subject, but also on many other organsims. And studies in these
organisms support and verify each other. I think in the US, the scientific
culture of studying "model" oganism is really prevailing and fruitful.

Did I answer your question?


在 oil (brother) 的大作中提到: 】
:
: i feel the jump might be big for most of us here
: i have a general puzzle: why bother to study worm?
: for beauty, for understanding, for cancer, etc
: the reason isn't strong enough to me now by somehow
:
: 【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: : Shen Kang is a faculty candidate and have got offer(s) from
: : Harvard/Stanford/Berkeley (which school, I don't know). His work is novel
: and
: : opened a big area.
: :
: : I hope every member of the JC at least read the paper pasted every week.
And
: : participate in the discussion if you feel it does help you to forge your
: : scientific thinking. And the one who is supposed to present take his/her
: duty.
: :
: : ---Assasin
: :
: :
: : 【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: : : MCBJC, cellular neurobiology, Mar. 10, 2003, by Assasin
: : :
: : : ***I decide to volunteer to make a presentation for the delayed and
missed
: : : MCBJC for this week. hope the folks who agreed to participate MCBJC take
: : their
: : : duty and keep it running.***
: : :
: : :
: : :
: : :
: : : paper:
: : :
: : : Shen K. and Bargmann C. I. (2003) The immunoglobulin superfamily protein
: : SYG-1
: : : determines the location of specific synapses in C. elegans. Cell 112,
: : 619-630.
: : :
: : : Comments:
: : :
: : : This is a good paper on synaptogenesis during C. elegans development.
: : : Synaptogenesis has been extensively studied in mouse and fly
neuromuscular
: : : junction. And it has enriched our understanding on the molecular and
: : cellular
: : : mechanism of synaptogenesis. Instead studying synaptogenesis in C.
elegans
: : is
: : : kind of new. So this paper sort of addressed an almost untouched
: fundamental
: : : question in cellular neurobiology, that is how a specific synaptic site
is
: : : chosen from many potential contacting sites a neuron’s axon makes.


--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 136.152.]
发信人: Marble (小石头哥哥), 信区: Biology
标 题: Re: MCBJC, cellular neurobiology, Mar. 10, 2
发信站: The unknown SPACE (Wed Mar 12 14:22:29 2003), 站内信件

is pdf available now for this paper, which is pretty new?
if so, could you send me a copy to [email protected]
pretty interesting one, and they utilize the power of
genetics in c elegans, particularly the well established
system for vulval development. Cori Bargmann is pretty
productive, i think she used to be postdoc of Horvitz, rt?



--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 128.118.]
发信人: assasin (冷血---何时能被加热？), 信区: Biology
标 题: Re: MCBJC, cellular neurobiology, Mar. 10, 2
发信站: The unknown SPACE (Sat Mar 15 00:04:08 2003) WWW-POST

How do you like this paper? It's pretty good, ha?

Cori Bargmann is in my "list of 100 productive PI in North America". she was a
postdoc of Horvitz.

【 在 Marble (小石头哥哥) 的大作中提到: 】
: is pdf available now for this paper, which is pretty new?
: if so, could you send me a copy to [email protected]
: pretty interesting one, and they utilize the power of
: genetics in c elegans, particularly the well established
: system for vulval development. Cori Bargmann is pretty
: productive, i think she used to be postdoc of Horvitz, rt?
:
:
:


--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 136.152.]
发信人: Marble (小石头哥哥), 信区: Biology
标 题: Re: MCBJC, cellular neurobiology, Mar. 10, 2
发信站: The unknown SPACE (Mon Mar 17 13:49:14 2003), 站内信件

【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: Synapse formation
: Questions:
: 1). What’s unique about the methods the authors used to study synaptic site
: specification?
: 2). Why C. elegans is a good organism to address synaptic specificity issue?
: 3). In the syg-1 mutant, the synaptic vesicles are just displaced a little bit
: anterior. Why weren’t they transported to the very anterior termini where the
: HSN neuron synapses on other targets?
: 4). A problem about the paper is that they couldn’t characterize well the
: SYG-1 expression pattern. So, in the functional study, they express syg-1::gfp
: transgene under unc-86 promoter which is much stronger than the syg-1
: promoter. So it’s an overexpression experiment. What flaws could this cause
: to the explanation of SYG-1’s function?


this is very neat work. they used the nematode to address the factors that
are involved in localization and formation of stereotyped synapses. they
found that vulval epithelial cells are involved in the formation of synapses
at the vulva between HSNL and VC neurons.

talking about the general strategy, they first used YFP or GFP directed by
certain promoters that are "specific" to the synapse as markers, and they
demonstrated that they could visualize the formation of synapses near the
vulva. while the system has been established, they set out to address what
types of cells are involved in the synaptogenesis, using a variety of cell-type
specific ablation mutants. this is what i like best about this paper, and in
general, the nematode system; there are so many mutants that have been
generated during the last several decades, and cell lineage for many cells
have been characterized, genome has been sequenced and genomic libraries
are available, etc. once they found that mutant lacking vulva epithelial cells
are defective in the approapriate localization, they carried out a screening
that affect the localization (question, i think they used many already established
mutants, right?), and they identified a mutant syg-1. with genome sequenced,
they found it was the gene SYG-1 by genetic mapping and transformation
rescue (you cannot do this in mouse, think about ppl spending so many years
to functionally clone a "candidate" gene for certain genetic diseases). this
gene, syg-1, encodes a 727 aa novel transmembrane protein in the IG
superfamily. then they demonstrated the cell autonomy of SYG-1 in HSNL
by directing its expression in the HSN neurons to rescue the defective
synaptogenesis in syg-1 mutant (question,at first i thought that SYG-1 is
localized to the epithelial cells, now it turns out that it might be a receptor
on the HSN neurons. so what are the signals from the epithilial cells?)
the problem to study SYG-1 is that its expression is very weak, and they
had to use another stronger promoter. this might lead to unexpected expression
in other regions of the worm (they used unc86::SYG1::GFP). actually, it is
clear that they get specific expression pattern, while the pattern is different
from another transgene unc86::SNB, which suggests the specificity for the
SYG1 promoter. virtually, i think they should still have some other mutants
that they have not published (maybe Shen takes it as his faculty research).
i would focus on the epethilial cells and try to find the signaling pathways
that are involved. for example, while RNAi has been successful with the worm,
i would do a tissue-type specific RNAi using epethilial cell type specific
promoter, and then characterize the mutants that are defective in the
synaptogenesis of HSN/VC neurons near the vulva.

very nice job, particularly when you think about the genetics they have used
in the study.












--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 128.118.]
发信人: kandel (迷路的小孩Mao JJ的弟弟), 信区: Biology
标 题: Re: MCBJC-call for discussion
发信站: The unknown SPACE (Sun Mar 16 20:01:56 2003) WWW-POST

I read the paper briefly, and I'm still not clear what the authors want to
claim. But the paper is helpful to think the synapse formation issue more
broadly. that it's perhaps not only the pre or postsynaptic factors can
tragger the specificity and differenticiation of pre/postsynapse,but probably
the envirmental factors can also contribute to this process. what's is crucial
is to clarify which is more predominant. But all the work is in C.E, for
mammalian, we should get some powerful system to do this kind of research. Who
has some smart idea to build up an powerful system or assay to investigate
this question in mamalian??

as far as I know, even you block the mEPSC, and there are no spontanouse
transmitter release, there are still clusters of AMPA receptors. how can they
achieve that?



【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: Marble, kandel and others, have u read the aper and have sth to say?
:
:
: 【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: : MCBJC, cellular neurobiology, Mar. 10, 2003, by Assasin
: :
: : ***I decide to volunteer to make a presentation for the delayed and missed
: : MCBJC for this week. hope the folks who agreed to participate MCBJC take
: their
: : duty and keep it running.***
: :
: :
: :
: :
: : paper:
: :
: : Shen K. and Bargmann C. I. (2003) The immunoglobulin superfamily protein
: SYG-1
: : determines the location of specific synapses in C. elegans. Cell 112,
: 619-630.
: :
: : Comments:
: :
: : This is a good paper on synaptogenesis during C. elegans development.
: : Synaptogenesis has been extensively studied in mouse and fly neuromuscular
: : junction. And it has enriched our understanding on the molecular and
: cellular
: : mechanism of synaptogenesis. Instead studying synaptogenesis in C. elegans
: is
: : kind of new. This paper addressed an almost untouched fundamental
: : question in cellular neurobiology, that is how a specific synaptic site is
: : chosen from many potential contacting sites a neuron’s axon makes.
: : The authors indentified an Ig superfamily protein, SYG-1, as a candidate
: : receptor for synaptic specificity. What’s surprising is that the signal
for
: : SYG-1 is not from the post-synaptic partner, the VC neurons. Instead, it’
s
: : coming from the neighboring vulval epithelial cells. So it seemed that the
: : pre- and post-synaptic apparatus for constructing the synapse are not the
: : factors responsible for specifying where the synapse is going to form. The
: : factor is from the epithelial cell onto which the axon branch does not
form
: : synaptic button. The results suggest the following model of synaptogenesis
: in
: : C. elegans.
: :
: : Guide post signal
: : 1 1
: : 1 1
: : 1 1
: : V 1
: : Receptor on axon (SYG-1) 1
: : 1 1 ??

--
寻人启事: 那个PPMM愿意做偶的JJ呀? 请联系Kandel帥哥@ MIT BBS.

~~~~O~~~~~


※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 162.129.]
发信人: assasin (冷血---何时能被加热？), 信区: Biology
标 题: Re: MCBJC-call for discussion
发信站: The unknown SPACE (Sun Mar 16 23:00:13 2003) WWW-POST

Which system in Zebrafish is good? Visual system? At stanford, Stephen Smith
lab is studying synaptogenesis in zerafish optic tectum. But he is definitely
not the leader of this area. who else?


http://frd.stanford.edu/frd.lasso?-database=bluebook2.fmp&-layout=profile&-res
ponse=profile.lasso&-recordID=32911&-search


【 在 Morphin (莫非你是飞鸟；我养鱼) 的大作中提到: 】
: mammal is too complicate, try fish system.
:
: should not be very difficult to study synapses in fish.
:
: but Ig family is too diverse, or I am thinking to clone SYG-1 in fish.
:
: 【 在 kandel (迷路的小孩Mao JJ的弟弟) 的大作中提到: 】
: : I read the paper briefly, and I'm still not clear what the authors want to
: : claim. But the paper is helpful to think the synapse formation issue more
: : broadly. that it's perhaps not only the pre or postsynaptic factors can
: : tragger the specificity and differenticiation of pre/postsynapse,but
: probably
: : the envirmental factors can also contribute to this process. what's is
: crucial
: : is to clarify which is more predominant. But all the work is in C.E, for
: : mammalian, we should get some powerful system to do this kind of research.
: Who
: : has some smart idea to build up an powerful system or assay to investigate
: : this question in mamalian??
: :
: : as far as I know, even you block the mEPSC, and there are no spontanouse
: : transmitter release, there are still clusters of AMPA receptors. how can
: they
: : achieve that?
: :
: :
: :
: : 【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: : : Marble, kandel and others, have u read the aper and have sth to say?
: : :
: : :
: : : 【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: : : : MCBJC, cellular neurobiology, Mar. 10, 2003, by Assasin
: : : :
: : : : ***I decide to volunteer to make a presentation for the delayed and
: missed
: : : : MCBJC for this week. hope the folks who agreed to participate MCBJC
take
: : : their
: : : : duty and keep it running.***
: : : :
: : : :
: : : :
: : : :
: : : : paper:
: : : :
: : : : Shen K. and Bargmann C. I. (2003) The immunoglobulin superfamily
protein
: : : SYG-1
: : : : determines the location of specific synapses in C. elegans. Cell 112,
: : : 619-630.
: : : :


--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 136.152.]
发信人: Morphin (莫非你是飞鸟；我养鱼), 信区: Biology
标 题: Re: MCBJC-call for discussion
发信站: The unknown SPACE (Mon Mar 17 15:33:31 2003) WWW-POST

i think in terms of synaptogenesis the neuro-muscular junction is well studied
in mice. so if one wants to study fish, he should definitely go for the
synaptogenesis in CNS.
Retino-tectal projection is a good system to study axon guidance. so is it for
the study of synaptic plasticity too. If i am gonna do that, probably I will
avoid those hot spots. In fact, our lab is gonna study the reticulo-spinal
curcuits in zebrafish. So I guess the synapsis formation in spinal cord may be
worth studying.



【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: Which system in Zebrafish is good? Visual system? At stanford, Stephen Smith
: lab is studying synaptogenesis in zerafish optic tectum. But he is
definitely
: not the leader of this area. who else?
:
:
:
http://frd.stanford.edu/frd.lasso?-database=bluebook2.fmp&-layout=profile&-res
: ponse=profile.lasso&-recordID=32911&-search
:
:
: 【 在 Morphin (莫非你是飞鸟；我养鱼) 的大作中提到: 】
: : mammal is too complicate, try fish system.
: :
: : should not be very difficult to study synapses in fish.
: :
: : but Ig family is too diverse, or I am thinking to clone SYG-1 in fish.
: :
: : 【 在 kandel (迷路的小孩Mao JJ的弟弟) 的大作中提到: 】
: : : I read the paper briefly, and I'm still not clear what the authors want
to
: : : claim. But the paper is helpful to think the synapse formation issue
more
: : : broadly. that it's perhaps not only the pre or postsynaptic factors can
: : : tragger the specificity and differenticiation of pre/postsynapse,but
: : probably
: : : the envirmental factors can also contribute to this process. what's is
: : crucial
: : : is to clarify which is more predominant. But all the work is in C.E, for
: : : mammalian, we should get some powerful system to do this kind of
research.
: : Who
: : : has some smart idea to build up an powerful system or assay to
investigate
: : : this question in mamalian??
: : :
: : : as far as I know, even you block the mEPSC, and there are no spontanouse
: : : transmitter release, there are still clusters of AMPA receptors. how can
: : they
: : : achieve that?
: : :
: : :
: : :
: : : 【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: : : : Marble, kandel and others, have u read the aper and have sth to say?
: : : :
: : : :
: : : : 【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: : : : : MCBJC, cellular neurobiology, Mar. 10, 2003, by Assasin
: : : : :
: : : : : ***I decide to volunteer to make a presentation for the delayed and
: : missed
: : : : : MCBJC for this week. hope the folks who agreed to participate MCBJC
: take
: : : : their
: : : : : duty and keep it running.***

--
山脚一隅，草屋一间，良田三分，医书百卷，房前清溪，可凭垂钓，屋后药院，遍种百
草，采天地精华，解万家病痛，渔樵耕读，孜孜不倦，此愿得偿，我心足矣。

※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 141.211.]