The base composition of RNA from nucleoli formed at two different organizers in Chironomus tentans

Vol. 18, No. 3,1965

BIOCHEMICALAND 8lOPHYSlCALRESEARCHCOMMUNICATIONS

THE BASE COMPOSITION OF RNA FROM NCCLEOIiI FORMEDAT TWO DIFFERENT ORGANIZERSIN CHIRONOMJSTENTANS J.-E. Edstrijm Department of Histology, University of Gothenburg, Sweden. Present address: Department of Histology, University of he&, Sweden. Received December 4, 1964 In animal be templated a quantity

by less large

Hopkins, It

and plant

elusively

locally

and Leblond et al.

RNA is,

the cistrons

of nucleolar

Sirlin

formation

(1960),

synthesized

Chipchase

ha8 been shown clearly are 8ydheBiZed are two pair8

1963).

alternative for

locally

(Pelling,

of nucleolar

(1960),

or whether at other

tentans

organizers,

one at the 8eCOnd and

attribute

are separated chemical

into

difference8

dUCt8, difference8

of metazoan

two group8 between that

might

cell8

however,

RNA formation possibly

the DNA molecule8 not always 341

is in

or even of Chiro-

for nucleolar

Could,

it

case there

no WG a general

the cistrons

Bonner,

the nucleoli

chromosome. This type of distribution

that

of the

or not,

one at the third

nomus. The fact

(1961),

of whether

that

In this

Amano

parts

would be true

1964).

ex*

the nucleolar

Irrespective

Chironomus

1964).

and the nucleolar

1959; wOOd8, 1959; Rho aa

and Birnstiel,

in Borne cases the latter

et al.,

Sisken and Kinosita

or completely,

ma Micou,

to'

(McConkey and

are located

by McMaster-Kaye

(1964),

partly

cistrons

1963; Perry

(1961) and Pelling

genome (Goldstein 1961;

whether

a8 believed

(1960),

several

and Birnstiel,

of dispute

RNA is thought

of the genomic DNA, but still

enough to contain

at the loci

RNA formed

the nucleolar

than a percent

1964; Chipchase

is a matter

Perry

cell8

express

and their

reflect pro-

themselves

vol. 18, No. 3,1965

BIOCHEMICAL

morphologically.

AND BIOPHYSICAL

The question

whether

positional

differences

vestigated

by microelectrophoresis

leoli

individually

Ch. tentans followed placed

isolated

glands

were placed

in a droplet

from salivary

acid

The coverslip

was placed,

with

third leoli.

analyses

On account

with

difference

nucleoli

still

wetted

by the de Fon-

could easily

be

from the second and

in groups of 5-10 nuc-

ribonuclease

solution,

(Edstr6m,

1564),

hydrolysed and two

and Discussion

standard

RNA concentration

clean and the analyses

It was therefore

possible

errors.

In spite

and the composition

I).

342

the RNA

comparatively

to determine of this

was found between the two groups,

cases (Table

and

and a needle.

the cells

maneuvered

of the high nucleolar

of six animals,

5 min,

were run of each extract.

are relatively

moderate

for

on a coverslip forceps

with

separately

by microelectrophoresis

Results

accurate.

acid

needles,

with

(3rl)

min. A gland was then

from the chromosomes and nucleoli

and analyzed

extracts

acid

larva@ of

chamber and the chromosomes

The swollen

RNA was extracted

or three

l-2

inverted,

chromosnme were pooled

chromosomes.

instar

a watchmaker's

two glass

brune micromanipulator. disengaged

for

on top of an oil

were isolated

from nuc-

and Methods

of the 50 $ acetic

removed with

has been in-

gland

in ethanol-acetic

the secretion

acid

are any base com-

of RNA components

removed from fourth

by 50 $ acetic

by acetic

there

between the two nucleoli

Materials Salivary

RESEARCH COMMUNlCATlONS

the mean values no significant

each consisting

agreed well

in the two

8lOCHEMlCAL

Vol. 18, No. 3, 1965

AND BIOPHYSICAL

RESEARCH COMMUNICATIONS

Table I Moles of base in percent of the sum + standard error of the mean

Source of nucleolus

adenine

guanine

cytosine

uracil

Chromosome II

3l.eO.3

22.eO.2

18.eO.3

27.720.4

Chromosome III

3O.eO.4

22.2iO.3

18.8+_0.6

28.3+_0.5

As has been recorded the base composition content tent

of adenine

of adenine

hand it

ribosomal 1962;

nucleolar

RNA (Perry

The results that

be detected point

that

there

in other

to a high degree of similarity,

to the result8

of

RNA base analyses

segments not involved

in nucleolar

marked and significant

differences

menn, 1962).

The present

of Beermann (1960), valence

results

between Ch. tentans

with

is a precursor

of

and Baltimore, 1964;

1965). are negative

in the sense

are differences

too small

qualities. contrasting of different

in this

a complete and even their

respect

chromosomal

RNA formation, are found

between which

(Edstriim

and Beerthe studies

functional parts

equi-

in hybrid8

and Ch. pallidivittatus.

The work wa8 eupported by the Swedish Cancer Society. thanks are due to Dr. W. Beermsnn and Dr. U. Groesbach for supplying animal8 and in8tI?UCtiZIg in their care. Excellent technical assistance was given by f&s. I. Skald. 343

to

They do, however,

are in harmony with

demonstrating

between the organizers

partly,

1963; Brown end Gurdon,

on base composition

or differences

RNA, in agreement

1963 and 1964; Franklin

1964; Edstriim,

they do not exclude

has a high

of DNA. On the other

the cytoplasmic

and Birnstiel,

McConkey and Hopkins,

the bulk

RNA, at least

it

1962)

not as high as the con-

although for

1962,

and Beermann,

in the sense that

and uracil,

resembles

Chipchase

(Edstram

is unusual

and thymine

closely

the view that

earlier

My

Vol.18,No.3,1965

BlOCHEMlCALANDBlOPHYSlCALRESURCHCOMMUNICATK)NS

Referencee Amano, Y. and Leblond, C.P., Bxp. Cell Ree. 20, 250 (1960). 263 (1960). Beemann, 'II., Chromoeoma~, Brown, D.D. and Gurdon, J.B., Proc. Nat. Acad. Sci. U. S. 21, 139 (1964).

Chipchaee, Y.I.H. and Blrnetiel, ILL., Proc. Nat. Acad. Sci. 0. S.'s, 1101 (1963). Ed&r&n, J.-E., & "Methods in Cell Phyeiologyt8, Vol. I, D.M. Prescott ed., p. 417, Academic Press, ITew York and London ( 1964). Edetri%n, J.-E., & ."The Role of the Chromoeomee in Development", 23rd Growth Symp., P. Locke ed., p. 137, Academic Prees, New York and London (1965). Ed&r&, J.-E. and Beermann, W., J. Cell Biol. 14, 371 (1962). Franklin, R.M. and Baltimore, D,, Cold Spring Harbor Symp. Quant. Biol. a, 175 (1962). Goldstein, L. and Hicou, J., J. Biophys. Biochem. Cytol. p,

301

(1959).

Mcconkey, E.H. and Hopkine, J.W., Proa. Nat. Acad. Sci. U. S. 51, 1197 (1964). McMaster-Kaye, R., J. Biophye. Biochem. Cytol. 2, 365 (1960). Pelling, C., Chromoeoma 2, 71 (1964). Perry, R.P., Proc. Nat. Acad. Sci. U. S. 8, 2179 (1962). Perry, R.P., Exp. Cell Res. a, 400 (1963 4- . Perry, R.P., Nat. Cancer Inst. Monogr. 14, 73 (1964). Perry, R.P., Errera, MI., Hell, A. and Mtrwald, H.9 J. BioPhye. Biochem. Cytol. 2, 1 (1961). Perry, R.P., Srinavaaan, P.R. and Kelley, D.E., Science a, 504 (1964). Rho, J.A., and Bonner, J., Proc. Nat. Acad. Sci. U. S. a, 1611 (1961). Sirlin, J.L., Exp. Cell Res. 1p, 177 (1960). Sisken, J.E. and Kinosita, R., Exp. Cell Res. ,& 168 (1961). 153 (1959). Woods, P.S., Brookhaven Symp. Biol. &

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