Original Repository: Alan Mason Chesney Medical Archives. Daniel Nathans Collection
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Medical Subject Headings (MeSH):
New Directions: Growth Signals and Cellular Responses, 1980-1999
Letter from Daniel Nathans to Antonio M. Persico (January 15, 1992)
January 10, 1992
Dear Dr. Nathans:
Three months ago I received from your laboratory cDNA probes for Zif 268 and FOS B. Since then I have performed several experiments
on Northern blots with total or poly(A)+ mRNA extracted from amphetamine- and saline-treated 7-8 weeks old Sprague Dawley
rats. The results I observed using the FOS B probe indicate it highlights a message that responds like cFOS to drug treatment,
but has a different size (approximately 4.0 kb) than the 5.1 kb size reported by Zerial et al. and confirmed by Nakabeppu,
Y. and Nathans, D. I would thus like to briefly describe to you the reasons for my perplexity regarding FOS B message size.
Zerial et al. (EMBO Journal-1989) describe a FOS B 5.1 kb mRNA message observed in stimulated NIH 3D3 cells. Yet the Northern
blots presented in Figure 4 (which I have copied for your convenience) display a FOS B message that runs faster than the 28S
rRNA. I have so far hybridized 5 blots with your probe, which hybridizes each time to a fragment located between 28S and 18S,
in a position practically identical to that displayed by FOS B message in Figure 4 of Zerial et al. If we are to believe
that 28S runs at 4.8 kb and 18S at 1.7 kb, it is difficult for me to see how this message could be 5.1 kb. Furthermore, a
3.9-4.0 kb estimate is confirmed also on 2 blots where I ran RNA ladders.
My first worry at this point was to insure that the probe that I was using was indeed the FOS B insert you had sent me, cloned
in pBluescript KS-. As you can see on the photo I am including, a digest with Eco, Pat and Bam gave fragments of the expected
size (bright bands), though suggesting the presence of a very minor contamination (faint bands). Furthermore, none of the
probes I had previously used from those same blots, namely, cFOS and beta-actin, gives bands overlapping with my "putative"
FOS B (see last figure). Finally, as you can barely see on this figure (I apologize for the quality of the copy), FOS B expression
is significantly activated by acute amphetamine administration, with a time course which is identical to that of cFOS.
In conclusion, I think I am using the right insert, what I detect behaves like cFOS and these FOS B bands located between
28S and 18S like in figure 4 of Zerial et al. are not "left-overs" from previous hybridization. In your paper "A
Naturally Occurring Truncated Form of FosB That Inhibits Fos/Jun Transcription Activity," you report Northern blots data
from several tissues confirming a 5 kb message size. About one month ago I have spoken with Laura Sanders, who told me she
had done a very small amount of work on the FOS B project and suggested I should contact you to ask your opinion on the matter.
I hope you will forgive me for stealing a bit of your time for an apparently minor issue, but I cannot come up with a valid
explanation. Yet, an answer to this question is necessary, before I proceed with my work. I would thus very much appreciate
your suggestions. If you prefer to contact me by phone, rather than by mail, I can be reached in Baltimore at 550-1464 (fax: