Differences in both expression and protein activity contribute to the distinct functions of AINTEGUMENTA compared with AINTEGUMENTA-LIKE 5 and AINTEGUMENTA-LIKE 7.

Three members of the Arabidopsis AINTEGUMENTA-LIKE/PLETHORA (AIL/PLT) transcription factor family, AIL5/PLT5, AIL6/PLT3, and AIL7/PLT7, exhibit partially overlapping roles with AINTEGUMENTA (ANT) during flower development. Loss of ANT function alone results in smaller floral organs and female sterility indicating that some ANT functions cannot be provided by these related transcription factors. Previously, we showed that expression of AIL6 at the same levels and spatial pattern as ANT could largely rescue the defects of ant mutants. This suggested that the functional differences between ANT and AIL6 were primarily a consequence of expression differences. Here, we investigated the functional differences between ANT and both AIL5 and AIL7 by expressing these two AILs under the control of the ANT promoter. We found that only ANT:gAIL5 lines with much higher amounts of AIL5 mRNA as compared with ANT could compensate for loss of ANT function. ANT:gAIL7 lines with AIL7 mRNA levels similar to those of ANT were able to rescue some but not all aspects of the ant mutant phenotype. Thus, expression differences alone cannot explain the functional differences between ANT and these two related proteins. Studies in yeast show that AIL5 and AIL7 have lower transcriptional activation activities as compared with ANT and AIL6 when bound to the consensus ANT DNA binding site. Our results suggest that differences in both expression and protein activity contribute to the functional specificity of ANT compared with AIL5 and AIL7.

Nasal Reconstruction: Defects that Cross Anatomical Subunits.

The nose plays a crucial role in the human experience, both aesthetically and functionally. The biomechanics of covering flaps, the importance of a firm framework, and the anatomical basis for aesthetic subunits are imperative concepts as one proceeds through the algorithm of reparative options. The subunits consist of three paired units-the ala, soft tissue facets (also known as soft tissue triangles), and sidewall, as well as three unpaired units-the dorsum, tip, and columella. Because many defects cross aesthetic subunits, it is critical to understand when to adapt the subunit principle and how or when to use a combination of techniques. It can be more challenging to apply the subunit principle to small grafts and local flaps of the nose. Convex subunits, such as the nasal tip and alar lobule, more frequently follow the subunit principle. In our practice, we adhere to a teaching of producing "straight lines and sharp corners." This applies to local flaps and grafts and focuses on keeping scar lines inconspicuous. In this article, we discuss approaches we follow for various defects along with technical pearls for performing these reconstructions. The subunit principle is more of a practice of thinking of resultant scars within a background of existing lines, reflections, and contour inflections.