Abstract
The linear expression of a gene can be interrupted by the well-known RNA introns and the recently discovered protein introns. In both cases, splicing mechanisms physically excise the unexpressed segments. In this article we describe a third category of introns that we call 'translational introns'. These functional introns are not excised through a splicing mechanism; instead, the translational machinery bypasses a segment of the coding sequence of an mRNA. We suggest that 'translational introns' are part of a regulatory mechanism that may sense changes in the rate of translation and thereby control the ratio of alternative gene products.
| Original language | English |
|---|---|
| Pages (from-to) | 294-296 |
| Number of pages | 3 |
| Journal | Trends in Biochemical Sciences |
| Volume | 18 |
| Issue number | 8 |
| DOIs | |
| State | Published - Aug 1993 |
| Externally published | Yes |
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Translational introns : an additional regulatory element in gene expression. / Engelberg-Kulka, Hanna; Benhar, Itaj; Schoulaker-Schwarz, Rachel.
In: Trends in Biochemical Sciences, Vol. 18, No. 8, 08.1993, p. 294-296.Research output: Contribution to journal › Review article › peer-review
TY - JOUR
T1 - Translational introns
T2 - an additional regulatory element in gene expression
AU - Engelberg-Kulka, Hanna
AU - Benhar, Itaj
AU - Schoulaker-Schwarz, Rachel
N1 - Funding Information: is not only lesss pecializedb ut also synthesiosf a proteint hatw ouldd iffer, Ac~=owL.c~mees basicallyd ifferent. Sincteh e trpR-ladZ at leasti n one of its domainsf,r omthe We thank F. R. Warshaw-Dadon gapi s not borderebdy m atchecdo dons, proteint hatwould haveb eend irected (Jerusalem, Israel)f or a critical reading the bypassinegv entd oesnot seem to by the completein formationo f the of the manuscripta nd Dr O. Amster-be mediatedb y a singlet RNA which gene.W henthe efficiencyo f bypassing Choder (Jerusalem, Israelf)o r her com- would recognizbeo tht ake-ofaf ndland-is as high as 100%a, s is the casef or T4 ments.T his research wass upportedb y ing sites,a s has beens uggestefdo r T4 gene6 0,t hep roductfo rmedb y theb y-grants from the United States-Israel gene6 0 bypassin|zg. We haver ecently passinge ventw ill be the only product Binational Science Foundation (BSF) suggesteda model fort rpR-lac'Zb y-of theg ene. Howevewrh, ent hee fficiency and by the endowmentf und for Basic passin~g4 A. ccordingt o OLr, hypothesis, of bypassinigs lower,a s in the caseo f Research Foundationi n Life Sciences: for trpR--lac'Zb ypassingto occur, the trpR, the product of the bypassing The Dorot Science Fellowship Foun-untranslaterde giono f the mRNAm ust eventi s synthesizeidn additiont o the dation administered by the Israel be loopedo ut, thus bringingt he bor-completper oducot f the 0 frameT. hus. Academyo f Sciencesa nd Humanities. ders of the bypasserde gioni nto close the efficiency otfh eb ypassinpgr ocess proximityR. ibosomem odellings tudies wouldd eterminteh er elativea mountos! References have indicatedt hat a ribosomec an the two productsfo rmed. Furthermore, 1 Cech,T . R. (1990) Annu. Rev. Biechem5.9 . accommodaat ef oldedm RNAl oopof a since the two proteinsa ree xpectedto 2 Mehel, F., Umesono, K. and OzekHl,. (1989) 543-568 considerablseiz e (possiblym orethan carry both a similar and a different Gene8 2, 5-30 55 nucleotidesd)u ringt ranslatiown ith-domain(s),t hey may be functionally 3 ChristopherD. . A. and Halhck, R B out unfolding it inth e process( Ada antagonistiFco. r exampleb,o thprotein 4 Belfort. M. (1991C)e ll 64.9-11 Nucleic Acids Res1. 7, 7591-7608 Yonat,p ers.c ommun.W). e suggestth at productsm ight retain a dimerization 5 Re,nhold-HurekB,. and Shub. D. H. (1992) a protein(s),o therwise engageidn the domain, but might differ in another Nature3 57, 173-176 process of protein synthesis, could actived omain,s uchas a DNA-binding 6 Hirata,R . et aL (1990) occasionally interacwt ith the mRNA domain. Thus. the translationabl y-7 YamashlroC, . T. et al. (1990) 6726-6733 sequences involved in trpR-lac'Z passingp roductc ould act as a domi-651-657 bypassing.T his would result in an oc-nant negative regulatory element, 8 Peder,F . B. ei aL (1992) Proc. NatlAcad ScL casional loopingo ut of the gap, causing inhibitingt he functiono f the complete USA 89, 5577-5581 it to be bypassed.W e have described 0 frame product byfo rminghetero-10 Shub, D. A. and Goodrich-Blair, H. (199C2e) lt 9 Davis. E O. etaL (1992) Ce1171.2 01-210 this model in more detail elsewher@. dimersw ithit. This kindo f regulatioins 71, 183-186 We are still investigatingt he exact na-commonf or many eukaryoticg enes, 11 Huang,W . M. et aL (1988) Sctence2 39, ture and function of thterp R,~p roduct. like the myoD2 ° and jun/fos families~ , 12 Weiss, R. B., HuangW, . M. and DunnD, . M. 1005-1013 The exampleso f bypassing described and we haver ecently attributedi t to (1990) Cell 62. 11 ,'-126 here mayb e the first exampleso f trans-trpR~ , This postulated functionfo r a 13 GestelandR, . F., Weiss, R. B. anti Ark~nsJ,. F. lational introns which eventuallym ay translational bypassinpgr oduct is par-(1992)S cience257, 1640-1641 be foundi n otherg enesa s well. ticularly attractiveb ecause it predicts 72, 121/130 14 Benhar, I. andE ngelberg-KulkaH,. (1993) Cell the formationo f beterodlmers between 15 Yanolsky,C , and CrawfordI,, P. (1987) in Conclusions and regulatoryI mplications dllferentp roductsof the same gene. It Eschenchlac ol, and Salmonella typhlmunum It seemsth att hel ineare xpressioonf can also explain how a bypassing ef Cellulara ndM olecularB tolo~(/N eldhaA, a genec anbe interruptebdy intronsa t flclencyo f as low as 5% mayh ave a regu-MagasamkB, ,, Schaechter, M. anUdm barger, F, C,, IngerhamJ,, L., Brooks.LowK, ,, threel evels:p re-translatlo(RnN A spllc-latory role. Such a functionw ould be E., eds), pp.1 453-1472,A merican Societoyf ing)i'5t;r anslatio(nb ypassing)H,12a,1n4d; interestingi f thee fficiencyo f bypassing Memblology post-translatio(np rotein splicing6)-I°. could be regulatedp articularlyb y spe-(1990) mP ost-Transcriptional Controofl Gene 16 Benhar, I,, Miller, C. anEdn gelberg-KulkaH,. The RNA and protein Introns are cific physiological conditions. Int he F_xpmssion(M cCarthyJ,. E. G. and Tulle, MF. ., excisedt hroughs plicing mechanisms.c ase of trpR, we have recently found eds), pp.5 91-602,Spnnger-Vedag Translationainl tronsa re not excised, that the ratio of the bypassingp roduct 17 Benhar. I.,M ~llerC, . and Engelberg-KulkaH,. but rathera re bypassedb y the trans-to that of frame 0 isi nverselyp ropor-18 Varmus, H.E , (1988) Science 240, 1427-1435 (1992) MoI. M#crotJio6l. , 2777-2784 lational machineryt:h eyare therefore tional to the level of translation initi-19 Parker,J . (1989) Microbiol. Rev5, 3, 273-298 functional introns. The sizes of the ation of trpR; whent he rate of translation 20 Benezra,R , et el. (1990) Celt61. 49-59 translationainl tronso f T4 gene6 0 and initiationi s low, the two trpR products 21 AuwerxJ,. and Sassone-Corst, P. (1991C)e ll E. coli trpR-lac'aZr ein the rangeo f 50 are synthesized in similar amounts". 22 Benhar, I.. Miller, C. anEdn selberg-KulkaH,, 64, 983-993 nucleotideas nd they both cause the Thus, translationalb ypassing may be J. Bactenol.( m press) translatingm echanismt o move to favored under conditionsw hen the rate anothefrr ame. Howeveitr s, eemsth ata of translationin itiationo r translationin frameshiftinegv entis not obligatory, general is low; the low density of the andt hesize oft het ranslationainl trons ribosomes alongt he mRNA template mayv aryand be limitedb y the ability may increaset he chancesf or bypassing of the translationaml achineryto skip to occur. Therefore,w ithoutexcluding informationin the mRNA. What then, other possibilities, we suggest that could bet he regulatoryfu nctionof translationailn tronsare part of a regu- these translational intronBsy? defi-latory mechanism that may sense nition, a translationianlt ron should changes in the rate of translationa nd cause thbey passinogf parto f the linear thereby control the rat=o between informatioinn thec odings equencoef a linear and nonlinear expression o! a gene. As are sult,i t shouldc ause the gene. 296
PY - 1993/8
Y1 - 1993/8
N2 - The linear expression of a gene can be interrupted by the well-known RNA introns and the recently discovered protein introns. In both cases, splicing mechanisms physically excise the unexpressed segments. In this article we describe a third category of introns that we call 'translational introns'. These functional introns are not excised through a splicing mechanism; instead, the translational machinery bypasses a segment of the coding sequence of an mRNA. We suggest that 'translational introns' are part of a regulatory mechanism that may sense changes in the rate of translation and thereby control the ratio of alternative gene products.
AB - The linear expression of a gene can be interrupted by the well-known RNA introns and the recently discovered protein introns. In both cases, splicing mechanisms physically excise the unexpressed segments. In this article we describe a third category of introns that we call 'translational introns'. These functional introns are not excised through a splicing mechanism; instead, the translational machinery bypasses a segment of the coding sequence of an mRNA. We suggest that 'translational introns' are part of a regulatory mechanism that may sense changes in the rate of translation and thereby control the ratio of alternative gene products.
UR - http://www.scopus.com/inward/record.url?scp=0027336980&partnerID=8YFLogxK
U2 - 10.1016/0968-0004(93)90039-P
DO - 10.1016/0968-0004(93)90039-P
M3 - סקירה
AN - SCOPUS:0027336980
VL - 18
SP - 294
EP - 296
JO - Trends in Biochemical Sciences
JF - Trends in Biochemical Sciences
SN - 0376-5067
IS - 8
ER -