The necessary involvement of both complementary strands of DNA in the specification of messenger RNA

Vol. 7, No. 6, 1962

BIOCHEMICAL

AND BIOPHYSICAL

THE NECXSSARYr~OL~

RESEARCH COMMUNICATIONS

OF BOTH COXKPLEXXEl'ARY STRAXDSOF DNA

IN 'ITIE SPECIFICATION OF MESSENGERRNA* Eunice Department

Received

Strelzoff**

of

April

Zoology,

of the

results

(1959)

into

pair

replacing

found

which

had produced

to

analogue

an error

to G!C transition

purine other

of mutations replication

the

**Present

arise

City.

with

analogue no further

in the

abs,ence

of

mutations

have

if

as in the

been in the

the

analogue

case of

an

(BU) or a-amino-

mutagen.

In the

only

increase

one

and pyrimi-

DNA replication

induced

of the

by their

purines

be expected

have

of Freese

induced

5-Bromouracil

as the

analogues

of transitions

in replication,

with

address:

result

as would

where

*This work was supported Foundation and the U.S. formed while the senior Service Training Fellow

mutations

Induced

(AP) were employed mutants,

hypothesis

replacing

pyrimidines.

of the

the

the

purines

continue

of base

that

DNA are

to another,

dines.

A:?

New York

action with

who has postulated

absence

Ryan

University,

mutagenic

consistent

incorporation base

Columbia

J.

9, 1962

studies yielded

and Francis

an initial

upon

analogue.

case

burst

additional This

of

DNA would

be

by grants from the National Science Public Health Service and was perauthor was a U.S. Public Health in Genetics.

Dept. of Microbiology, School of Nedicine, 471

New York University New York City.

Vol. 7, No. 6, 1962

expected

BIOCHEMICAL

if

error

the

was one of

G:C to A:T transition Auxotrophs

in

point-mutants, the

necessary

following for

phenotype.

for

the

and compared

with

expression

of mutations

induced

in an effort

to

determine

from

one or both

strands

base

analogues

first

were

absence

of

of found

the

pair

must

imposed

the

an error

in

after or AP. yielding

the

analogue,

genetic

code

themselves

according

A?,

is, read

The mutagenic

the

growth.

the

DNA during

the

The induced thereafter

to either

of

in the

the

patterns

that

could

both

in order

be drawn

members that

the

from

these

of a mutant

base

new phenotype

be

which

by

cell.

case of the met2

auxotroph,

replication,

mutant

third

doubling

Were only the

purine

the

was

for

DNA molecule.

arguments

be modified

In

reversions

1.

concluding

on the

of a proto-

required

into

to express

Two independent each

whether

of the

of DNA replications

number

synchronous

to be

to determine

expression

by the

of the

analogues

shown in Figure

data,

the

were incorporated

replication

mutants

the

of BU-induced

determined

pairs

incorporation

The number

expression

seemed

in order

a

a and b). base

and which

studied

were necessary

mutant

1962

1961;

manner,

of replications that

trophic

this

involving

15 whose relevant

were further

number

analogue

coli

RESEARCH COMMUNICATIONS

incorporation,

(Strelzoff,

of E.

were identified

AND BIOPHYSICAL

the

of DNA,

new phenotype,

it

phenotype

whether

one or either

strand should 472

reverts

the

is

imposed

mutagen

of DNA capable have been

is BU of

expressed

Vol. 7, No. 6, 1962

BIOCHEMICAL

REPLICATION ERRORS A:T

AND BIOPHYSICAL

DNA REPLICATION

RESEARCH COMMUNICATIONS

INCORPORATION ERRORS

A:T 1

J A:BU I I + G:BU

AP:T I 2

i/

AP.C 3

& px[ +

arg2-jarg2 arg4--+arg4+ meta-+

met2+

trY1-

+tryp

tw2--+try2+ his1 '+hisl+ Figure 1. Schemes for the production of mutants in g. a, based on the transition of single base pairs in DNA in response to the incorporation of 5-bromouracil (BU) or 2-aminopurine (AP) which have not been rejected by experiment (Strelzoff, 1961; 1962). The base pairs in rectangles are those which impose the new phenotype. after

two replications

expressed Ryan,

almost

Fried

(the

immediately

and Schwartz,

As expected,

strand

G:BU and h?:C

appears of

phenotype the mation

in

after

the

the only

second

and Wainwright,

behave

second the

imposed

half 473

as G':C in the

the

the

1958; 1961)). the

phenotype

the

fir&,

were the

genetic

time

phenotype

the

cell.

v?ere either

new message,

after

is

mutant

replication.

replication;

one strand,

and Wollman,

are made,

to yield

have been

of a prototroph

Jacob

do not

errors

DNA sufficient should

latest,

(Ryan 1954;

When incorporation invariably

phenotype

novel

or at infor-

BIOCHEMICAL

Vol. 7, No. 6, 1962

should

have

after

the

been thirll

of obtaining

the

consistent

with 1954)

The fact formation

that

(shulman

hydrogen

bonding

DNA helix

forms of

s.tranded

is not what

is

enable

work

of Wood and Berg

is not stranded Cn the --in

vitro

the

enabled

cell

DNA but other

hand,

synthesis

only

it

] *

is (Dunn and

of mutations

for

course,

the

of the

is

necessary for

the

by that

single-

for

of abnormal

the

unravellcd new

of

such as a part and double-

seem capable

forr,lation specific

of

facing

us, rather

of an LW4. which proteins.

that

protein

template

The synthesis

of a single-

on double-stranded ?&Vz is

proteins 474

by

?SA synthesis;

on the

single-stranded

formed

DNA strand

The question

formed

s.ingle-

alternate

indicates

.WA formed

of

that

if

formation

1962)

s.ynthesize (1962)

not

message,

both

of RNA.

is

the

in the

PJTA suggests

strand

and Berg,

to

by the

the

chance

which

or that,

1961),

In vitro,

necessary

will

as A:T,

production

or either

of

synthesis what

3% f (WI5

0 f messenger

way postulated

DXA (Chamberlain

however, asks

both

x
the

be ca.

double-stranded

complement

transfer

initiating

it

with

of DbTA unless,

the

the

of DHA seem involved

molecule

and Bonner,

an obligate

after

incorporation

of the

two strands

?JA is

in the

found

time

were true,

would

chemical

the

a and b).

of a single

stranded

of

and half

was never

A:BU and AP:T

kinetics

1962

messenger

strands

reads

tine facts

1961;

it

result

RESEARCH COMMUNICATIONS

second

hypothesis

obs.erved cell

the for

latter

and the

(Strelzoff,

either

the

the

Apparently

Smith,

after

replication,

In case

first.

tia?osed

AND BIOPHYSICAL

sufficient (Birenberg

D:L%. for and

the

Vol. 7, No. 6, 1962

Matthaei,

BIOCHEMICAL

1961).

formed

on the

understand to

of

It

the

would

comes

Feughelman

specifies

from

seems that --in vivo by which artifacts

helix,

suggested by the

the

truth

experimentation

of

Swartz

both

lie

1950; personal

propositions

provide

the

it

standards

in experiments

and Kornberg,

(1962).

if

J.,

these

must

can be recognized

(Trautner,

histone

Bonner,

1962;

and Berg,

by zubay

Bloch,

to

complementary

(Chamberlain

and Stedman,

1955;

is possible

composition

it

forming

RNA is

it

of DNA (Stedman

whatever

communication).

RESEARCH COMMUNICATIONS

of messenger

a base

such as that

groove et al.,

vitro

to have

DNA which

be prevented

major

s,trand

of a DNA double

by a mechanism

in the

--in

a single

pattern

how it

that

1962)

If

AND BIOPHYSICAL

performed

1962).

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D.,

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