ABSTRACT
A hybridisation analysis of a genomic clone library of Rhizobium galegae HAMBI 1174 located four EcoRI fragments homologous to the nod-box promoter sequence of Sinorhizobium meliloti in two separate gene regions. Two of the five nod-boxes detected in the R. galegae genome were carried on a single cosmid clone, pRg30, upstream from the nodABCIJ and nodF genes, whereas the other three nod-boxes were carried on a different cosmid clone, pRg10. Hybridisations with various nod gene probes from S. meliloti and Rhizobium leguminosarum species detected a nodD homolog in pRg10. The sequence data obtained from regions adjacent to each nod-box in pRg10 confirmed the presence of a second nodD in the R. galegae genome and, in addition, revealed the presence of nodN, nodU, dctA nifH and nifQ-like genes in pRg10. Thus, by using a promoter-specific nod-box probe we could identify a new region carrying genes involved in nitrogen fixation and host specificity functions.
Subject(s)
Genes, Bacterial , Plant Roots/microbiology , Promoter Regions, Genetic , Rhizobium/genetics , Symbiosis/genetics , Base Sequence , Cosmids , Molecular Sequence Data , Nitrogen Fixation , Restriction Mapping , Sequence Analysis, DNA , Sequence Homology, Nucleic AcidABSTRACT
A 36,688 bp fragment from the left arm of chromosome IV of saccharomyces cerevisiae was sequenced. Sequence analysis identified 20 complete non-overlapping open reading frames (ORFs) of at least 100 amino acids. Nine of these correspond to previously identified and sequenced genes: SIT4/PH1, FAD1, NAM1/MTF2, RNA11, SIR2/MAR1, NAT1/AAA1, PRP9, ACT2 and MPS1/RPK1. Three ORFs show homology to previously sequenced genes. One ORF exhibits a hypothetical yabO/yceC/YfiI family signature and one has the ATP-dependent helicase signature of the DEAD and DEAH box families. Six ORFs show no appreciable homology to any proteins in the database. One of these is identical to yeast expressed sequence tags and therefore corresponds to and expressed gene. In addition, two partial ORFs and 11 ORFs that are totally internal and are not likely to be functional were detected.
