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Ciliogenesis in human fetal airway epithelium occurs from 11 to 24 gestational weeks. Using genetic and antigenic markers specific for human axonemal dynein heavy chain 9, we characterized temporal aspects of axonemal dynein expression associated with large airway epithelial ciliogenesis during human fetal development. Late in the first trimester, an undifferentiated columnar epithelium is characteristic of the large airways, and immunocytochemical studies exhibited focal localization of axonemal dynein antigen on luminal epithelial cell borders at sites consistent with emergent ciliary beds. From 12 to 22 wk, immunocytochemical labeling of new ciliary beds was prominent, and localization within the cytoplasm of epithelial cells suggested avid synthesis of axonemal dynein in advance of ciliogenic events. Quantitative RT-PCR of tracheal RNA and in situ hybridization studies compared favorably with immunocytochemical findings with the earliest expression of axonemal dynein at 9-10 wk gestation. These studies have documented that axonemal dynein is expressed early in human fetal life during airway epithelial maturation and well before histological or ultrastructural evidence of ciliogenesis is apparent. cilia; ciliogenesis; human fetal airway epithelium

DNA probes identified 631 markers on the genomic map of Mycoplasma genitalium. Mapping of clones by hybridizing 20 overlapping cosmid and lambda clones revealed replica filters containing 856 genomic DNA clones. Hybridization data divided the clones into three groups: clones which hybridized to only one cosmid; clones which hybridized to two adjacent and overlapping cosmids; and clones which hybridized to several cosmids.

DNA fragments were obtained from the genome of Yersinia pestis using four restriction enzymes, SpeI, NotI, SfiI and AscI. SpeI producedthe largest sum of fragments, as analyzed by pulsed-field gel electrophoresis (PGFE), three of which contains comigrating fragments after two-dimensional SpeI-ApaI electrophorsis. In analyzing the non-pigmented mutant PGM- cells of Y pestis after digestion and PGFE, a missing fragment corresponding to a large deletion of about 92.5 or 106 kb determined by the specific endonuclease shows that this fragment has precise endpoints and is capable of encoding the eight peptides present in the pigmented strains.