Nucleolus organizer

locus: NO

locus_name: Nucleolus organizer

organism_type: B

chromosome_number: V

chromosome_side: L

link_group: VL

cultural_requirements: VL. Right of terminal sat (60, 817) and of terminal translocations ALS176, ALS182, and AR190. Left of lys-1 and of translocations AR30, AR33, AR45, NM130, AR177, and NM183; thus, left of caf-1 (60, 817; D.D. Perkins, N.B. Raju, and E.G. Barry, in preparation). T(OY321) divides the NO into two portions, each of which retains ability to form a nucleolus (D.D. Perkins, N.B. Raju, and E.G. Barry, in preparation). (821) Genes specifying 5.8S, 17S, and 26S rRNA (but not 5S) are located in the nucleolus organizer region in a tandemly repeated DNA sequence (215, 361). Wild type 74-OR23-1A has 185 tandem repeats (571). Nucleotide sequence of the 5.8S ribosomal DNA has been determined; comparison with yeast cells shows 145 of 158 rRNA residues conserved (974). Hybridization shows that sequences are shared both with Xenopus and Drosophila (216). T(AR33)produces duplications with two copies of the nucleolus organizer (817), which undergo demagnification (887) in such a way that different nontranscribed spacer sequences from both parental nucleolus organizers are retained (888). Genes specifying 5S rRNA are not included in the ribosomal DNA repeat unit, but are located elsewhere in the genome as dispersed single genes surrounded by heterogeneous flanking sequences (361, 975). For rRNA processing, see rip-1.

enzyme_id:

anid_name:

near_l: ALS176, ALS182, and AR190

near_r: lys-1, AR30, AR33, AR45, NM130, AR177 and NM183

neu_name:

supplement:

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Strains

FGSC #	Reporting Genes	Species

References

Authors	Title	Year
Barry, E. G. , and D. D. Perkins.	Position of linkage group V markers in chromosome 2 of N. crassa.	1969
Cox, R. A. , and K. Peden.	A study of the organisation of the ribosomal ribonucleic acid gene cluster of N. crassa by means of restriction endonuclease analysis and cloning in bacteriophage lambda.	1979
Cox, R. A. , and R. D. Thompson.	Distribution of sequences common to the 25-28S-ribonucleic acid genes of Xenopus laevis and N. crassa.	1980
Free, S. J. , P. W. Rice, and R. L. Metzenberg.	Arrangement of the genes coding for ribosomal ribonucleic acid in Neurospora crassa.	1979
Krumlauf, R. , and G. A. Marzluf.	Genome organization and characterization of the repetitive and inverted repeat DNA sequences inNeurospora crassa.	1980
Perkins, D. D. , N. B. Raju, and E. G. Barry.	A chromosome rearrangement in Neurospora that produces viable progeny containing twonucleolus organizers.	1980
Phillips, R. L.	The association of linkage group V with chromosome 2 in Neurospora crassa.	1967
Rodland, K. D. , and P. J. Russell.	Regulation of ribosomal RNA cistron number in a strain of Neurospora crassa with a duplication ofthe nucleolus organizer region.	1982
Rodland, K. D. , and P. J. Russell.	Regulation of rRNA cistron number in a double nucleolar organizer strain of Neurospora crassapossessing heterogeneous rDNA.	1982
Selker, E. , and C. Yanofsky.	Nucleotide sequence and conserved features of the 5. 8 S rRNA coding region of Neurospora crassa.	1979
Selker, E. U. , C. Yanofsky, K. Driftmeir, R. L. Metzenberg, B. Alzner-DeWeerd, and U. L. RajBhandary.	Dispersed 5S RNA genes in N. crassa:structure, expression and evolution.	1981