Korean Journal of Microbiology (미생물학회지)

The Microbiological Society of Korea (한국미생물학회)
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Isolation and Characterization of the nsdC Gene in Sexual Development of Aspergillus nidulans

Aspergillus nidulans의 유성분화에 관여하는 nsdC 유전자의 분리 및 분석

  • 김혜련 (원광대학교 자연과학대학 생명과학부) ;
  • 한동민 (원광대학교 자연과학대학 생명과학부)
  • Published : 2006.12.30
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Abstract

A lot of mutants which cannot initiate sexual development were screened and several loci including nsdA, nsdB, nsdC, and nsdD were identified in homothallic ascomycetes Aspergillus nidulans. The NSD206, which has nsdC6 allele, showed typical phenotype of NSD (Never in sexual development) mutants. The nsdC gene was cloned by transforming NSDP697 ($nsdC^-$, $pryG^-$) with AMA1-NotI genomic library. The transforming library DNA recovered from several transformants showing wild phenotype carried about 10 kb genomic DNA insert. The DNA sequence of nsdC was analysed using GPS (Genome priming system). The nsdC gene has an open reading frame (ORF) of 1,929 bp encoding a putative polypeptide of 643 amino acids. The NsdC carries $C_2H_2C_2H_2C_2HC$ type zinc finger DNA binding domains in the middle of the polypeptide. A coiled-coil domain at its C terminus were also found. In nsdC6 allele, a single T insertion was occurred between 407-408 bp leading to the frameshift mutation and early termination of translation producing the truncated protein which has only 139 amino acids.

사상성 진균인 Aspergillus nidulans에서 유성분화초기단계, 또는 유성분화유도를 위한 세포내 조건 형성과정에 관여할 것으로 예상되는 유전자를 탐색하였다. 선행연구결과를 통해 유성분화를 전혀 하지 못하는 NSD (never in sexual development) 돌연변이주가 분리되어 nsdA, nsdB, nsdC, 그리고 nsdD의 4상 보군으로 동정된 바 있다. 본 연구에서는 이들 유전자 중 nsdC 유전자를 분리하고자 A. nidulans AMAl-Not I Genomic DNA library로 nsdC6 돌연변이균주를 형질전환하여 야생형처럼 유성분화를 할 수 있는 형질전환체를 분리하고 이들로부터 약 10 kb genomic DNA가 삽입된 library DNA를 분리하였다. Genomic priming system (GPS)을 이용하여 nsdC6 돌연변이를 상보하는 유전자의 부분 서열을 확보한 후 전체 DNA 염기서열을 결정하였다. 유전자분석 결과 nsdC는 intron 없이 1,929염기(643개의 아미노산)로 구성된 Open reading frame (ORF)를 가지며, 약 1kb 정도의 비교적 긴 5'-UTR 부위에 2개의 intron을 가지고 있음이 확인되었다. 또한 NsdC polypeptide의 중앙에 $C_2H_2C_2H_2C_2HC$ 형의 zinc finger DNA binding domain과 C 말단 부위에 coiled-coil domain이 존재하였다. nsdC6 돌연변이는ORF의 407 bp와 408 bp사이에 엽기 T가 삽입되어 frameshift가 일어난 것으로 밝혀졌다. 따라서 nsdC6 돌연변이균주는 단지 139개 아미노산만 갖고 있는 결실 단백질이 생산됨을 알 수 있었다.

Keywords

References

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