Antisense strand of DNA
Ken Howe
I responded on Dec. 11th with pretty much the same answer you gave and
was "corrected" (sorry, I didn't save the message since it was the only
one I received and I'm pretty sure that my/our response is the correct one):
I wrote:
<<More simply put, the sense strand of a "DNA sequence which is
<<transcribed into RNA" is that strand whose sequence is identical to
<<that of the RNA (with the replacement of T's to U's), and so the antisense
<<strand is that strand whose sequence is complementary to that sequence.
<<The antisense strand is the strand which is read during transcription.
<<
On 14 Dec 1995, Mick Jones wrote:
>This is always a problem for new students to molecular biology.
>DNA is double stranded, and the DNA strand that is identical to the
>transcribed RNA (except for Us for Ts) is called the SENSE strand. The
>complementary strand, which acts as the template for transcribing the
>RNA is called the ANTISENSE strand.
Thanks for coming to my rescue.
Ken Howe
"the onions expressed here are my own"
Stephen R. Lasky
Mick and Ken:
I am going to do it again. That is "correct" you on this point. You are
both wrong. I sincerely hope you are don't teach molecular genetics to
students before you get this right. The sense strand is the strand that
is transcribed into mRNA and therefore is the anti-parellel complement of
the mRNA. I realize that this is contra-intuitive given the convention of
placing the strand that is equivelant to the mRNA on the top of published
sequences and also given the meaning of anti-sense RNA, but you both have
gotten it backward.
Mick, your really should check references from "the good old days" before
you cite them. If you go back and look any number of early molecular
genetics textbooks you will find definitions similar to:
1: "Since ... the resultant mRNA is translated in a 5' to 3' direction it
follows that the beginning of the gene will lie to the 3' end of the SENSE
STRAND (caps my own) and the conclusion of the gene will lie at the 5'
end. The sole function of the anti-sense strand is to generate a
complementary sense strand for use by the next generation of virus or
cell. The sense strand will give rise to an antisense strand during
replication". U. Goodenough, Genetics, circa 1980.
2: "The COPIED strand of DNA which contains the actual code for a protein
is known as the SENSE STRAND. Its partner is known as the antisense
strand." R.A. Woods. Molecular Genetics (i think), circa 1978.
Please note that in the definition of the sense strand is the strand that
is copied by the RNA polymerase. It is read in the 3' to 5' direction,
polymerizing ribonucleoside triphospates into a strand growing the the 5'
to 3' direction that is anti-parellel and complementary to the template
(sense) strand.
I would give you more quotes, but I have donated all of my old genetics
books to charities that take them to Central America but another book that
I suggest for all students of molecular genetics, that is "Molecular
Genetics" by Gunter Stent. While this book is dated (as is Goodenough's
statement about the anti-sense strand) it is extremely well writen and
gives you an historical perspective on the early development of molecular
genetics.
If you can find published works that substantiate your definition of the
sense strand as being the same as the mRNA, I would appreciate the
references.
Ken, since you are in the UC system, I suggest you make an intercampus
call to a couple of classical geneticists so that you can get this right.
You might want to call D.E. Morse (one of the early workers on Trp
attenuation with C. Yanofsky and one of the first persons to show the
polarity effect of nonsesnse mutations), E. Englesberg and N. Lee (who
defined postive regulation of gene expression in the Ara operon), or even
R. Sinsheimer who used to be at UCSC. All of these people are now at
UCSB, and except for Sinsheimer, are the scientists who I learned genetics
from.
As I said, given our current conventions, the definition of a sense strand
is contra-intuitive, but as scientists, when there is a question about a
definition, it would serve you well to go back to the literature in order
to make sure you have it right.
--
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Stephen R. Lasky Ph.D. Brown U/Roger Williams Medical Center, Providence, RI.
Phone: 401-456-5672 Fax: 401-456-6569 e:mail: Stephe...@brown.edu
===================================================================
America may be unique in being a country which has leapt from barbarism to decadence without touching civilization. John O'Hara.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Francisco G da Nobrega ib - bio 7588
I found your comments really precious. Maybe it is high time that some=20
sort of strict convention is negotiated between molecular geneticists=20
because every textbook writer apparently feels entitled to devise its own=
=20
"intuitive"or "logical" rules. One can marvel at the multitude of=20
conventions just by reading the comments by Tanaka & Macer (TIG=20
10:417,94) and Coddington or Sam (TIG 11:124,95). You learn that Lewin=20
(Genes V) calls the 5'->3' strand "sense" while the template strand is=20
now the antisense or noncoding.
Maybe a teleconference held between the big textbook writers=20
(Alberts,Darnell,Suzuki,Zubay, Mays,etc. etc) with the participation of=20
some classical geneticists could settle the matter at the beginning of=20
the postgenome era (Science, 20 Oct 95)...
Happy Hollidays!
=09=09=09=09Francisco
F.G. Nobrega
Universidade de S=E3o Paulo
Biologia - IBUSP
C.P. 11461
05422-970 S=E3o Paulo - SP - Brasil
Voice: (011) 818-7588 Fax: (011) 818-7553 E-mail: fgdn...@usp.br
Stephen R. Lasky
Maybe it is time to define some sort of convention although I'm not sure
that you will get a lot of interest in doing so. During the 50's and 60's
(before my time) and 70's (not before my time), there was a convention;
the template strand was considered to be the sense strand.
I believe that the confusion about which strand was the sense strand
was in the early to middle 80's when riboprobes were first used to probe
for transcription off of one strand or the other. To further add to the
confusion, there is anti-sense RNA, that is actually, the same sequence
as the sense strand of the DNA.
The one thing that is true whether you call it sense or anti-sense is that
the strand of DNA that is transcribed is the template strand that codes
for an RNA that can be translated into protein. The problem with calling
the sense strand the template strand is that during replication, both
strands are template strands. In fact, even during transcription, both
strands can be used as template strands.
Personally, it makes more sense to me, 8-), to call the template strand
the sense strand since if you transcribed and translated the opposite
strand (the anti-sense strand), most of the time you would come up with a
peptide that doesn't make any sense (or do anything, although there are
exceptions to this). Maybe that strand (the anti-sense strand) should be
called the non-sense strand, but then we might get that confused with
nonsense mutations. So maybe it should be called the not-sense strand.
Maybe we should just call it the TOP strand, since convention dictates
that the strand that has the same sequence as the mRNA is always put on
top of published sequences. 8-)
SRLasky
--
Stephen R. Lasky
term "sense strand" in earlier versions of Genes. It would be interesting
if different definitions have been used by a single author over the
years. Maybe it is time to redefine the terms so that they are more
intuitive given the current usage of anti-sense vs sense, but, as I
pointed out to Francisco, anything you call the sense (or anti-sense)
strand is frought with problems.
I think that the logic used originally was that the if you transcribed the
sense strand, it would make sense when you translated that mRNA into
protein. If you transcribed the opposite strand (the anti-sense strand
since it was anti-parellel and complementary) you would not get an mRNA
that could be translated into a meaningfull protein.
SRLasky
> Stephen:
> Mike and Ken are in good company. Lewin in GENES V p.163 says that the
> strand that bears the same sequence as the mRNA is the coding or sense
> strand. In GENES IV p. 113 he called it only the coding strand. The
> other strand is called the template or antisense strand. This is a mess
> (template, coding, sense...and plus/minus has not been mentioned)!
>
> Best regards,
> Herb
Herbert H. Winkler
Mike and Ken are in good company. Lewin in GENES V p.163 says that the
strand that bears the same sequence as the mRNA is the coding or sense
strand. In GENES IV p. 113 he called it only the coding strand. The
other strand is called the template or antisense strand. This is a mess
(template, coding, sense...and plus/minus has not been mentioned)!
Best regards,
Herb
On Fri, 22 Dec 1995, Stephen R. Lasky wrote: