Anhyd obiosis
Plan desicca ion gene
ound in a nema ode
When subjec ed o d ough condi ions,
some o ganisms en e a s a e o
suspended anima ion known as
anhyd obiosis1, su i ing o inde ini e
pe iods un il ehyd a ion allows hem o
esume no mal me abolism. We ha e iden i-
ied a gene in he anhyd obio ic nema ode
Aphelenchus a enae ha is up egula ed in
esponse o desicca ion s ess and whose
encoded p o ein sha es sequence simila i y
wi h a la e-emb yonic gene ha is induced
in many plan s when hey a e dep i ed o
wa e . This inding sugges s ha animals
and plan s ha unde go anhyd obiosis may
use common p o ec i e s a egies agains
dehyd a ion, and p o ides a uni ying insigh
in o he mechanism o anhyd obiosis.
A cha ac e is ic ea u e o anhyd obio ic
o ganisms is hei syn hesis o high concen-
a ions o non- educing suga s du ing he
induc ion o anhyd obiosis1. Fo example,
A. a enae accumula es la ge amoun s o
ehalose in esponse o dehyd a ion, and
his co ela es wi h i s desicca ion ole -
ance2. T ehalose p o ec s memb anes and
p o eins om desicca ion damage by
eplacing s uc u al wa e 1, and con ibu es
o he o ma ion o an in acellula o ganic
glass3which is hough o s abilize he cell’s
con en s. In anhyd obio ic plan s, suc ose
has a simila unc ion4.
Howe e , se e al lines o e idence indi-
ca e ha non- educing suga s alone a e no
su icien o con e a s a e o anhyd obiosis,
and ha u he adap a ions a e equi ed5,6.
A class o p o eins known as LEA ( o ‘la e
emb yogenesis abundan ’) p o eins accu-
mula e in esponse o wa e de ici in many
plan s, and hese a e pa icula ly abundan
in anhyd obio ic plan s such as he esu -
ec ion plan C a e os igma plan agineum,
and in ma u ing seeds and pollen7. We
he e o e in es iga ed whe he simila genes
a e p esen in A. a enae.
We ound ha se e al genes a e up egu-
la ed in A. a enae nema odes unde going
anhyd obiosis du ing exposu e o 90% ela-
i e humidi y o 24 hou s. O pa icula
in e es was a s ongly induced ansc ip
wi h a leng h o abou 675 bases (Fig. 1a, b),
which encodes a p edic ed p o ein o 143
esidues. The sequence o his p o ein indi-
ca es ha i is a membe o he g oup-3
subclass o LEA p o eins8; i con ains a leas
ou copies o a cha ac e is ic 11-me mo i ,
and u he echoes o his mo i a e p esen
h oughou he sequence (Fig. 1c).
The g oup-3 LEA mo i has been p o-
posed o o m an amphipa hic a-helix ha
di ec s he oligome iza ion o he p o ein9.
These p o eins a e ex emely hyd ophilic
and a e esis an o dena u a ion by hea —
p omp ing sugges ions ha hey help o p e-
en damage by wa e s ess, o example by
ac ing as hyd a ion bu e , molecula chap-
e one, ion sink o memb ane s abilize 1,9.
Suc ose glasses a e s abilized in i o by
in e ac ion wi h a pu i ied g oup-3 LEA
p o ein om Typha la i olia pollen10. Non-
educing suga s and LEA p o eins may
he e o e ac syne gis ically4,10 o p omo e
he o ma ion o a s able ‘bioglass’ in he
cy oplasm o anhyd obio ic plan s and in
desicca ion- ole an seeds and pollen — he
bioglass may ap agile biological mol-
ecules in ime and space, and p ese e hem
om desicca ion damage. I he newly
iden i ied LEA p o ein in A. a enae also
s abilizes ehalose glasses in his way
du ing desicca ion, he bioglass model o
anhyd obiosis can be ex ended o include
anhyd obio ic animals.
Genomic11 and pa ial p o ein12 sequence
in o ma ion indica es ha LEA p o eins may
be used by o he nema odes as a de ence
agains wa e s ess. The genomes o some
mic oo ganisms also con ain sequences ha
encode LEA-like p o eins (al hough exp es-
sion o hese has no ye been demons a -
ed11), including he desicca ion- ole an
Deinococcus adiodu ans, which also encodes
enzymes o he biosyn hesis o ehalose. A
bioglass s a egy o anhyd obiosis could be
widely used in biological sys ems and may
ha e o igina ed in ancien cell ypes ha
we e exposed o wa e s ess.
John B owne*, Alan Tunnacli e†,
Ann Bu nell*
*Depa men o Biology and Ins i u e o
Bioenginee ing and Ag oecology,
Na ional Uni e si y o I eland Maynoo h,
Coun y Kilda e, I eland
e-mail: ann.bu [email protected]
†Ins i u e o Bio echnology, Uni e si y o
Camb idge, Tennis Cou Road,
Camb idge CB2 1QT, UK
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(1975).
3. C owe, J. H., Ca pen e , J. F. & C owe, L. M. Annu. Re . Physiol.
60,73–103 (1998).
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327–333 (1997).
5. Higa, L. M. & Wome sley, C. Z. J. Exp. Zool. 267,120–129
(1993).
6. Ga cía de Cas o, A. & Tunnacli e, A. FEBS Le . 487, 199–202
(2000).
7. Ing am, J. & Ba els, D. Annu. Re . Plan Physiol. Plan Mol.
Biol. 47,377–403 (1996).
8. Du e, L. e al. Plan Mol. Biol. 12,475–486 (1989).
9. Du e, L. Plan J. 3, 363–369 (1993).
10.Wolke s, W. F. e al. Biochem. Biophys. Ac a 1544,196–206
(2001).
11.Du e, L. P o ein Pep . Le . 8,115–122 (2001).
12.Solomon, A., Salomon, R., Pape na, I. & Glaze , I. Pa asi ology
121,409–416 (2000).
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38 NATURE
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Figu e 1 Desicca ion induces exp ession o a p o ein in he nema ode
Aphelenchus a enae
ha is homologous wi h ano he emb yonic
p o ein p oduced by a plan unde simila ci cums ances. a, Exp ession o he
A. a enae
la e-emb yonic gene
Aa lea1
in esponse o
desicca ion s ess, as e ealed by no he n blo ing using an
Aa lea1
p obe: lane 1, con ol RNA om esh un ea ed nema odes; lane 2,
RNA om nema odes exposed o 90% ela i e humidi y o 24 h. b, Same blo , bu his ime hyb idized wi h an 18S RNA p obe as a
loading con ol. c, Local alignmen (
P
42
e
119) o a 121-amino-acid o e lap be ween he p edic ed sequences o
Aa lea1
(GenBank
accession numbe AF423069) and an emb yonic p o ein om he Eu opean whi e bi ch (
Be ula pendula
; accession numbe S39475).
S39475 was he mos closely ela ed LEA-3 sequence o
Aa lea1
ha we we e able o de ec in he GenBank da abase. The e a e a
leas ou copies o he cha ac e is ic 11-me LEA-3 mo i (highligh ed).
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