TY - JOUR
T1 - Organization of the flaFG gene cluster and identification of two additional genes involved in flagellum biogenesis in Caulobacter crescentus
AU - Schoenlein, P. V.
AU - Gallman, L. S.
AU - Ely, B.
PY - 1989
Y1 - 1989
N2 - In Caulobacter crescentus, mutations have been isolated in more than 30 flagellar genes (fla, flb, and flg) which are required in the cell cycle event of flagellum biogenesis. The flaF and flaG mutations and two newly identified mutations, flbT and flbA (P. V. Schoenlein and B. Ely, J. Bacteriol. 171: 000-000, 1989), have been localized to the flaFG region. In this study, the genetic and physical organization of this region was analyzed, using the cloned 4.0-kilobase flaFG region in the recombinant plasmid pPLG727. Plasmid pPLG727 complemented flaF, flaG, flbA, and flbT mutations. Further complementation studies with pPLG727 derivatives indicated that flaF and flbT are unique but overlapping transcription units, whereas flbA and flaG constitute a single transcription unit. To determine the direction of transcription of the putative flbA-flaG operon, the promoterless chloramphenicol transacetylase gene was inserted into various positions in the flbA-flaG region, and merodiploid strains containing these transcriptional fusions were assayed for gene function and expression of chloramphenicol resistance. These results showed that transcription proceeds from flbA to flaG. To confirm the complementation analysis, Southern analyses were performed on chromosomal DNAs isolated from strains containing insertion and deletion mutations. Taken together, these studies defined the relative gene order at one end of the flaYG flagellar gene cluster as flgL-flaF-flbT-flbA-flaG.
AB - In Caulobacter crescentus, mutations have been isolated in more than 30 flagellar genes (fla, flb, and flg) which are required in the cell cycle event of flagellum biogenesis. The flaF and flaG mutations and two newly identified mutations, flbT and flbA (P. V. Schoenlein and B. Ely, J. Bacteriol. 171: 000-000, 1989), have been localized to the flaFG region. In this study, the genetic and physical organization of this region was analyzed, using the cloned 4.0-kilobase flaFG region in the recombinant plasmid pPLG727. Plasmid pPLG727 complemented flaF, flaG, flbA, and flbT mutations. Further complementation studies with pPLG727 derivatives indicated that flaF and flbT are unique but overlapping transcription units, whereas flbA and flaG constitute a single transcription unit. To determine the direction of transcription of the putative flbA-flaG operon, the promoterless chloramphenicol transacetylase gene was inserted into various positions in the flbA-flaG region, and merodiploid strains containing these transcriptional fusions were assayed for gene function and expression of chloramphenicol resistance. These results showed that transcription proceeds from flbA to flaG. To confirm the complementation analysis, Southern analyses were performed on chromosomal DNAs isolated from strains containing insertion and deletion mutations. Taken together, these studies defined the relative gene order at one end of the flaYG flagellar gene cluster as flgL-flaF-flbT-flbA-flaG.
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U2 - 10.1128/jb.171.3.1544-1553.1989
DO - 10.1128/jb.171.3.1544-1553.1989
M3 - Article
C2 - 2921244
AN - SCOPUS:0024544119
SN - 0021-9193
VL - 171
SP - 1544
EP - 1553
JO - Journal of Bacteriology
JF - Journal of Bacteriology
IS - 3
ER -