Fig. 3.

SARS-CoV2 Nsp6, Orf6 and Orf7a transgene expression leads to reduced tracheal branching in Drosophila. a Graphic representation of branching in human lung (left) and Drosophila trachea (right). b Typical tracheal branches in wild type larva (w¹¹¹⁸). Left panel, overview of complete Drosophila trachea system. Red box denotes area shown at higher magnification in middle panel, as well as area covered in images shown in c. Right panel, labeling of tracheal branches: red, central branch; green, class I terminal branch; and, blue, class II terminal branch. c Representative images of tracheal branches (taken at location equivalent to red box in b in SARS-CoV-2 Nsp6, Orf6 or Orf7a overexpression (OE) transgenic flies. Arrow indicates a missing class II terminal branch based on wild type (w¹¹¹⁸ shown in b). Tracheal branches are labeled to indicate the central branch (red), class I terminal branch (green), and class II terminal branch (blue). d Quantification of tracheal branch numbers in one segment. N = 6 larvae per group. Results are presented as mean ± SD. Statistical significance (*) is defined as P < 0.05