Document Detail

X chromosome nucleolus organizer mutants which alter major type I repeat multiplicity in Drosophila melanogaster.
MedLine Citation:
PMID:  6308398     Owner:  NLM     Status:  MEDLINE    
The nucleolus organizer (NO) of the D. melanogaster X chromosome is composed of ribosomal repeat units which contain two types (I and II) of non-rDNA insertions (In+) and repeats with no insertions (In-). Evidence from other laboratories indicate random interspersion of all types of repeat units within the X NO. An EcoRI and BamHI examination of rDNA from two bobbed mutants, bb2rI and mal12 demonstrates segregation of the major type I repeat units. The 46 rDNA repeats of the bb2rI NO contain no detectable major type I repeats whereas the majority of the 68 rDNA mal12 repeats are major type I and tandemly linked. This observation suggests that gross deletions of rDNA can result in nucleolus organizer regions with predominantly one type of repeat unit. Additivity tests demonstrate that the 46 ribosomal repeats of the bb2rI chromosome revert the phenotype of other bobbed NOs, but the 68 mal12 ribosomal repeats show no or slight additivity. This is in agreement with the observation that In+ repeats do not significantly contribute to functional rRNA. A Southern blot analysis using BamHI which cuts only in type I insertions demonstrates that the majority of major type I In+ repeating units exist in tandem linkage group(s) within the X NO.
Z D Sharp; V V Gandhi; J D Procunier
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Molecular & general genetics : MGG     Volume:  190     ISSN:  0026-8925     ISO Abbreviation:  Mol. Gen. Genet.     Publication Date:  1983  
Date Detail:
Created Date:  1983-09-23     Completed Date:  1983-09-23     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0125036     Medline TA:  Mol Gen Genet     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  438-43     Citation Subset:  IM    
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MeSH Terms
Cell Nucleolus / physiology*
DNA Restriction Enzymes / diagnostic use
Drosophila melanogaster / genetics*
RNA, Ribosomal / genetics*
Repetitive Sequences, Nucleic Acid
X Chromosome
Grant Support
Reg. No./Substance:
0/RNA, Ribosomal; EC 3.1.21.-/DNA Restriction Enzymes

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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