©=)

1992 Oxford University Press

Nucleic Acids Research, Vol. 20, No. 13 3509

Nucleotide sequence of transfer RNA genes from the linear mitochondrial DNA of the yeast Wiliopsis mrakii and Pichia pijperi Nathalie Dinouel, Frederic Sor and Hiroshi Fukuhara* Institut Curie, Section de Biologie, Batiment 110, Centre Universitaire Paris XI, Orsay 91405, France EMBL accession

Submitted June 11, 1992 In most species of yeast, the mitochondrial DNA (mtDNA) is a circular molecule. Only two species have been reported to have a linear mtDNA (Williopsis mrakii, synonym Hansenula mrakii

A-T T-A T.C

T-A A-T

T

TAA C

TAG

C

C

A /A A-T T / T T-A T / A T-A A/A T T A-T T T C-C T T T

T

C

TCTA 1111 ACAT

T

C

TT

T

TM

A

ATCGG

C

,-C

T-A C-C C-C

A-T C

A

T

C

A

C A T

T

Met (P.p.)

fMet (P.p.)

A

A C-C

G-C

C-C

C-C

A-T

T-A

C-C

A-T

A-T C-T

C-C

T-A

T-A T

T T

C

C

T

TAG

A

C

A-T T C-C

T T

T

A A

REFERENCES 1. Wesolowski,M. and Fukuhara,H. (1981) Mol. Cell. Biol. 1, 387-393. 2. Kovac,L., Lazowska,J. and Slonimski,P. (1984) Mol. Gen. Genet. 197, 420-424.

C-C

T-C A

A

T T T T

Lys (W.m.)

Leu @.m.)

(W.m.)

C

C-C

T-A

A

C

A

T

T

T / T T A

C-C

C A

T A

C C

A

A C/

A-T

T T G

AAACA

C

TI

T

11111

(1) and Candida parapsilosis (2)). After a systematic survey we have found that many other species of yeast have also a linear form of mtDNA. As these genomes lead us to ask questions about their origin, we analyzed several tRNA genes in the linear mtDNA of W.mrakii and Pichia pijperi (Figure 1). We found that the gene divergence between W.mrakii and the circular Saccharomyces cerevisiae and Kluyveromyces lactis mtDNAs was not significantly greater than the difference between the two circular mitochondrial genomes (identity more than 80% in average). P.pijperi tRNA genes seem to be somewhat more divergent from the circular DNAs (60-81 % identity). No specific traits of change were detected in the genes of linear mtDNA. Analysis of protein coding sequences (cytochrome oxidase subunit 2 gene of W.mrakii and apocytochrome b gene of P.pijperi, not shown) suggested that the linear genomes use a standard yeast mitochondrial code. Figure 2 indicate the map position of the tRNA genes in the mitochondrial genomes. The linear structure of Pichia pijperi mtDNA will be fully described elsewhere.

A

ACTCC

/ C A

C-C

T

MCT

T

C

T

A IT

C

T C-CC T C-C A-T A-T A-T A G A T

T

T

ACAC

C

C

X66437-X66444 (incl.)

T T

TCACC III1

AA

A

AAMAG

6TC III

c

C

T

A

11111

TAA

CTCTG

A-T

TTTTC

T

A

CCCAC

TC

T-A

G

III

GIn

T

A

T A

A

C

A

CTA

C-C C-C

C

A

T T

T

A-T A-T T-A T-A 6-C

A

T

C

T

C

AGTC C

T

T T

CAAAG

TTCG 1111 AACC

C

T T

cmc 11111

T-A

1111 C

C

A

T

TCAC

A

ATACC

T

A-T A-T T-A T T A-T

TAA

A

C T T A-T A-T

C

T

T

A

A

T A

Leu (P.p.)

A

TCTCC 1.111 T

T A C

AA

T A

T

A

11111

ACGC

G

A-T

A

TACCC

T

6CCG III

C-C

6-C

C-G

C-C

T

A-T

T-A

A-T T-A C-C A-T

nos

L M fM

P.p. A-T

c-C

T T

CTTAC

ACCC

C

1111

C

TC

T C

C-C

T

A

T

III

C

T CGC

Pro (W.m.)

CA

A

A

/C A C-T A / T T-A C / T-A A / T A A A-T T T T-A A T A T T T A c T

Ser CW.m.)

mitochondrial DNAs, presented in cloverleaf form of tRNA.

To whom

vr

T

Figure 1. Transfer RNA gene sequences in P.piyperi (P.p.) and Wmrakii (W.m.)

*

KQL PS

A C

T T

C

AGAT

C

T

C

C-C A T-A T-A T-A

ACTA

C

TT

A

ACCC

C

C

°

T A

Iil AGCAC

C T

C

1.111

TCCTC

T

A

CCATC

A A

C A

x

A-T A-T A-T A-T T-A

6-C

A-T T-A A-T A-T

H--

0

c c-C

C-c

correspondence should be addressed

H 1-4

I-I

0 >

C

0 142 I 0

W.m. I-I O

i

30 >

I-I C0

500 0 I

10

20

30

I-l

N

40

Kbp

50

Figure 2. Map position of tRNA genes in P.pijperi and W.mrakii mitochondrial genomes. Single-letter amino acid codes are used to indicate tRNA genes.