Emphasizing text when composing mails?

Hi,

Gnus has the feature to display some words with a different
face if they are bracketed with certain characters (*bold*,
/italic/, _underline_).

Is there a command for the opposite direction when composing
mails, i. e. I write a paragraph, I want to mark up "for
example" as bold, so I select those words as a region, M-x
some-gnus-or-emacs-command, and the text changes to "*for*
*example*"?

Org does not appear to have a function for this, and
markdown-insert-bold of markdown-mode
(https://jblevins.org/projects/markdown-mode/) uses doubled
characters ("**bold**").

TIA,
Tim