ABSTRACT
Incremental differences in delta-aminolevulinate dehydratase (ALA-D; the second enzyme of the heme biosynthetic pathway) activity among inbred mouse strains can be attributed to variation in the number of copies of the ALA-D gene. We have cloned and characterized the Lv locus from an inbred mouse strain (DBA/2J) that has three times the normal ALA-D activity levels. The entire 12-kb ALA-D gene plus 16 kb of flanking DNA are found in 28-kb tandemly repeating units. We used the derived nucleotide sequence surrounding the internal junction of the repeats to survey wild-caught mice and demonstrate that multiple copies of the ALA-D gene occur in 7 of 24 worldwide locations of Mus domesticus mice. Data are consistent with a model that high lead (Pb) in the environment may be providing a selective advantage to mice harboring multiple copies of the ALA-D gene, since the enzyme is potently inhibited by lead.
Subject(s)
Gene Dosage , Levulinic Acids/metabolism , Porphobilinogen Synthase/genetics , Animals , Base Sequence , Cloning, Molecular , Cosmids/isolation & purification , Male , Mice , Mice, Inbred DBA , Microsatellite Repeats , Molecular Sequence Data , Multigene Family , Porphobilinogen Synthase/isolation & purification , Porphobilinogen Synthase/metabolism , Recombination, Genetic , Regulatory Sequences, Nucleic AcidABSTRACT
We have sequenced the Petunia hybrida gene that specifies the proteolipid subunit of the mitochondrial Fo ATP synthase and have used this gene to investigate plant mitochondrial gene transcription. The Petunia atp 9 gene contains a single open-reading frame capable of specifying a 77 amino acid-polypeptide that is homologous to bovine, fungal and maize proteolipid subunits. S1 protection identified 3 transcripts in a ratio of 1:5:100 in the Petunia tissues tested. The transcripts share a common 3' terminus but have 5' termini that map 528, 266, and 121 nucleotides upstream of the translation start site. The 5' terminus of the longest transcript maps to the sequence ATATAGTA, which is nearly identical to the yeast mitochondrial transcription initiation site ATATAAGTA. Primer extension analysis indicates that these two shorter transcripts are not due to splicing. The two shorter transcripts originate at sequences homologous to sites at 5' termini of two pea and maize genes. These consensus sequences may signal processing events other than splicing.
Subject(s)
DNA, Mitochondrial/genetics , Proton-Translocating ATPases/genetics , Amino Acid Sequence , Base Sequence , Chromosome Mapping , Genes , Macromolecular Substances , Plants/genetics , Proteolipids/genetics , RNA Processing, Post-Transcriptional , Sequence Homology, Nucleic Acid , Transcription, GeneticABSTRACT
The genetic compositions of two independently derived preparations of the Bratislava-77 strain (B77) of Rous sarcoma virus were analyzed after each was passaged seven or more times in duck embryo fibroblasts. RNase, T1-resistant oligonucleotide fingerprint analysis of virion RNA from both preparations of duck-passaged B77 revealed the presence of two large noncontiguous deletions. Approximately 75% of the RNAs contained a deletion which spans oligonucleotides 304 to 4 on the viral genome (about 3,500 nucleotides) and encompasses all of the B77 polymerase gene. More than 90% of the RNAs also contained a deletion which spans src-specific oligonucleotides 6 and 5(about 2,200 nucleotides) and is identical to the deletion observed in transformation-defective B77. Virion RNA from duck-passaged B77 also contained two oligonucleotides (D1 and D2) not observed in the RNA of B77 virus grown on chicken embryo fibroblasts. Analysis of the virion RNA of duck-passaged B77 by denaturing agarose gel electrophoresis revealed four major subunits with molecular weights of 3.40 x 10(6), 2.65 x 10(6), 2.25 x 10(6), and 1.55 x 10(6). Whereas the 3.40- and 2.65-megadalton (Mdal) RNA species comigrated with the nondefective and transformation-defective RNAs of B77 propagated on chicken embryo fibroblasts, no counterparts to the 2.25- and 1.55-Mdal RNAs were observed in the RNA of B77 grown on chicken embryo fibroblasts. Oligonucleotide fingerprint analysis of these RNA species revealed that the 2.65-Mdal RNA contains the src-specific deletion and that 2.25-Mdal RNA contains the polymerase region deletion; both of these deletions were observed in the 1.55-Mdal RNA, which was the major RNA subunit species detected in duck-passaged B77. The new oligonucleotides (D1 and D2) observed in the duck-passaged virus were present in the 2.25- and 1.55-Mdal RNA species in vitro and in vivo and directs the synthesis of a 130,000-dalton protein (p130). p130 contains antigenic determinants specific for p27 (gag gene) and gp85 (env gene) but does not contain sequences which cross-react with antisera directed against the alpha beta form of RNA-dependent DNA polymerase (pol gene). This RNA, therefore, is generated by a fusion of the gag and env genes of Rous sarcoma virus B77.
Subject(s)
Antigens, Viral/genetics , Avian Sarcoma Viruses/genetics , Genes, Viral , Viral Proteins/genetics , Avian Sarcoma Viruses/immunology , Base Sequence , Mutation , RNA, Viral/analysis , RNA, Viral/genetics , RNA-Directed DNA Polymerase/geneticsABSTRACT
A T particle of vesicular stomatitis virus, containing most of the L-gene region, has been isolated. In vitro, these T particles synthesize exclusively a small adenine-rich RNA that is complementary to the T-particle genome. Partial sequence analysis of this small RNA indicates that it is an RNA of unique sequence with a length of approximately 45 nucleotides.
