Direct imaging of the InSb001-c8 x 2 surface: evidence for large anisotropy of the reconstruction.

We have observed the InSb(001)-c(8 x 2) surface by using high-resolution transmission electron microscopy in the profile-imaging geometry. All images observed at temperatures up to 420 degrees C agree well with the c(8 x 2) model reported by Kumpf et al. [Phys. Rev. Lett. 86, 3586 (2001)]]. 1/30 sec real-time observations at 420 degrees C evidence that a part of the subsurface and surface layers (called a gull-type segment) undergo switching to and from a bulk configuration. The finding is suggestive of large anisotropy in the mean square displacement of the c(8 x 2) surface.

Genomic structure and chromosome mapping of the genes encoding clathrin-associated adaptor medium chains mu1A (Ap1m1) and mu1B (Ap1m2).

The protein mu1B is a member of the medium chain family of the clathrin-associated adaptor complex and is expressed exclusively in epithelial cells. We determined the genomic structure of previously cloned murine genes for mu1B (Ap1m2) and its closely related homolog, mu1A (Ap1m1). Comparison of their genomic structures revealed that the positions of introns are identical between these two genes, except for the insertion of an additional intron in Ap1m1 (intron 4). By contrast, these structures are different from that of the more distantly related Ap2m1 gene encoding mu2. Taken together with the similarity of amino acid sequences among these genes, the data presented in this study suggest that Ap1m1/2 and Ap2m1 diverged long before the separation of Ap1m1 and Ap1m2, which most likely resulted from a relatively recent gene duplication. We also mapped AP1M2 to human chromosome 19p13.2 and Ap1m2 to the proximal region of mouse chromosome 9. The results are consistent with the fact that these regions are syntenic.