A cull-fre% 5. co11 m&m +cPd lacorporatiag syrtsrra dap%md%nt
upon the iladdition ofxsaxlger or tamplate l@iA hrs bmm obtakmd
(Hirenberg &ad MAtthAei, Roe. lOIt. AC!&. SC%., 47, 1988 (2960)).
Both nAtUK&2ly OccUrrfn$ d 6pthtbti.C ~~ytikrout1%otlidAS hrve
be%n found to direct .prot%in 6yatiw6iS fn this 63VStA6L `@I% pl9.W66
of this invert~Fgrtfon wfll be to t%mlpAre the cb4tracteri6tiss of
naturally occurrirtg urd syrkthetic golyMxmucleotide coding wits.
?hASA &A3?ACt%rf8tfcS Wit2 %x&CkudA (A) th CQdb# fAti0, %.a., the
mmber of nuc2eotidPs ooapris&zq one coding uait (b) rpecifielty
of coding units, i.e., whmther tvo ox IK)IC% coding unfts direct the
incmporrtion of one Nina aefd iato protain, end (d) the universality
of cod- units, i.e., whether I codlag uait correspondiq to sn
amino acid is ths am in differsat spcacieo.

  Polyuridylk Add 661~86 %B t&nplat% RNA by directing the c%22-
frem syatherie of polyph%xky2828nin% (#irenb%rg and Matthaei, Proc.
BAt. t%C8d; SCi., 2, i488 (1960)). Aho, rAndusly saixmd polynucbo-
tide direct th% lntmpWAt%On of other ~~SXB acids iat gr~tsh.
Thus, the aucbotide coPlporitima of RNA crtdiqg wnlto aO3XASpanding
to 25 amino acids has b%en dgrtannirtrrd (Martin, Matthaei, Soa6a md
Hirenberg, Biochem. Biophys. RAr. Caeas. (in press)).

   The acldftion of tobacco mmaic virus ItHA to the tzell-free
&. e02i SySt%SI FAAtly
iaf%O~rAtiOa of amino acids into
protein.  Thea roluble 6 f&tpu2%t%d
              -protein fommd duriq tha CGUrSB of the
reaction he6 m6ny prsopertfee characteristic of tobccco ameoic virus
pro teti.  ?Or eXen@le, %t %6 ant&mic and $6 precipitated by
tobacco BY)SA~L: viruo urtibody~ it ablly be purified by O&U colurm
chromatography in th* seme memet AS tobacco mosaic ttiruc protein;
a peptide can be iro2Ated from the middle of the molacule after
digestEon with tryprin which oamtrins Cl&smino acid in the prop%r
plm~e (Tsugit&, R~Ql&Oatrrt und ttir%nb%rg, unpubtished results).
Rowever, the pro&et of the ration did not CDabine with tobacco
DIln6Ad.C VirU6 I t0 f&S iaf%CtiV% VirUS.  The product eppears to
be sf&.lAr, but sot id%ntiesl to tobucco moraic virus protcrin.
Atte6tpt6 will be pude to -Are the ffngrr-prkrts of the product
of the reaction and authentic tObACc0 rarosic virus protein snd thU6
det%rmin% tb% prA&ise differ%nc%s batvmm thus. Thus% studi%
should 6how wb%tb%r codkrg units contained irr tohccc, xwsstc virus
IMA cm direct the synthesis of skpilsr protmin6 in both tobacco
plants and 5. coli.  fn other words, a direct comparison may be
obtained betwe~be function of RN4 coding units in two different
6pdtci.W.


  Selublo RN4 haa bea ohmat to be an iaternwdiata in poly-
phenylalurine Sj?lkth96iS (8ir%nb%r& ncttthaei And Jana6, Proc.
Mat. AcAd. Sci. (in praoo)).  Siace wlub2e &#A appears to b& a
adacUr which fuwtioas AS an %daptar'* carrying un at&m acid
to its proper p2acs on tmmpiato RNA, A varirnl soluble RNA tkase-
pAtrfi%g With A different c?odt iatter of t%SQdAt% l@#A would
substitutr on% amino rrcid for another during protein aynthtbsis.
It is possible thut in sp4W.%s other than &. coli, poiyuridy2ic
acid FRAY b% eithar 6&%Aning2%68 of BUY S%N% A~t66it@At%~fO~ 6
diffsrant amino Acid.  Solubls mtrtA will bris purified fro61
d 1% f%r%at rp%ciao and wf 2 be chArgod maymaticotly with different
c  -mdao Acids. The C ii -ssino aeyl soluble RtUs ui22 Be us%d in
A purified g. coli 8t6itW Acid iWO~l=Atilk# SySt@R Atid synthetic
~l~iboS!Ul&%O~S will be add%d to direct amino acid isscorporation.
It 4.6 ho@ that dAtA obtainard from th%s@ auperiwate wilt 6how
whether soluble WA fmm different rpaci%6 cm r%co@te the 6~m
Rm wdiag u&it.  ThaS% brtA, A% w%22 66 th% %xp%r$m%ntrs mntfoaed
pr%viou62y, CMjr indicate Wh%th%r R.&I coding units in differaant
6$WiWi%6 AT% th% IAIM.

   btandom2y mixed polyurydilic-guAnylic Acid dir%cte th%
incorporAtion of a nu&%r of m&?o Acid6 IacludinS E%ucin% And
VA2h6.  Tbs AlSkOtmtS Of 2%UCina AQd VAliSSA iXiC.O~rAtAd intO
prot%iaa u%re equal and wtrer proportiouaF to the -lie acid
contmt of each polymer.  ThUS, tb aumber of cod- units pr%vei2-
L"il
C1  in leucine prar polpeer were t:taa s4me. ISowev%r, omi6sim of
  -valfne did not affect the incorporatjxrn of C24*2eucizw, which
dmcmstrrted that the coding units for va2i.x~ inLd l%ucinca ar%
differant.  D%g%n%racy in this 6yrtcwo 6x66 demmhsltrated by the find-
i~g tfnat both polyuridylic-gupnylie Acid And polyuridylic-cytidylic
Acid 6tkaulstad the iabforporatioa of leucine into protein.

  The ap%c&ffcity and d%gsnemcy of iUiA coding units in tobacco
mosaic virus RM#L will br +sosat@&ed in A siorilar OpaMer.  Thus,
tha inforarrtion concerning th% coda which bLIa &am obtained wing
synthetic po2ynuc2eotidos may b% diractly compared with the coding
charact%riatic6 of A virrl RNA.

  (b and c) ThiO type of trsinixq in enarysnololky and bioch&m&cal
gamtics will aid Dr. Bym%a &n hi6 futur% ressarch. Upon
compl%tion of hi6 fetlowahip, Dr. Byrne6 should be %xceptiunal2y
us11 qualified to do indapandent r%s%arch and to tracb.

yaCi2$ti%6 AvAiiAbla

  Th% Laboratory of Xolecu2ar Biology in the Itmtitute of
Arthriti6 and Metrbolic D~s%As%@, Hatfond Institutes of Health,
oil2 contain AU of the %quipm%At aacetasary for this type of work.
This iaborrtory is rtrffed by peopl% trAiu%d in diff&rent disciplines,


such (~9 cry1#t8llogr@y, phySical ch%mirtry, biophysics, argwie
ClbdSt~, bimclmeirtry and @m%tiCr. `Irrtlart&ctiozk &tad %X&I&IQ%
of faf@rmathtbotwaern SW& p%opie rhouldbavalurrble endDx.Bym%s
should obkia training of ummtully broad aature.  Rquent fntor-
dt8CipiiAA~ S%ldMrt h%lp t0 &6Ai&AiA % StiRAdAtiIig fl3t@lf%ctUAi
aad rrrasrch emvirmt.

  An -2 stipILB(I for Dr. 3Qrmm of $6,500, Xt will not b%
WCt%tBSArjr t@ r%CdV% th% iXWtitUtiC?I&A2 AiiOW&QC!A iA pAPtiA2 PAyapbnt
of watts faownred by the mt:ionri rQ6titutco of wk%Itb faa purwukce
of Dr. Byrms' r4kaeAreh 6nd trainLag, Part of tkoo fuad.8, howw%r,
snpy b% an old to Dr. Byrne in dofr~~ tuition %aqmm%a of %L%ctfw%
COF8rS@@ @RiBSl At tb #rti@QAi ~QStitUtQS Of iz%Ulth if Da. Byraes
wishes to participAta IQ them.