How to increase/decrease quote level in mail/usenet message?

[Grant Edwards]

The other text editors I've used for editing email and nntp messages
(and most of the GUI mail/news programs) all had commands to
increase/decrease the quote level for a selected block of text.  I use
emacs for editing source code and almost all other tasks, but I
haven't been able to switch to using it as my mail/usenet editor
because I've never been able to find the command in mail-mode or
message-mode to increase/decrease the quote level for a block of text.

My fingers are programmed to do "ctrl-C >" and "ctrl-C <" to
increase/decrease indentation/quoting, but that doesn't work. Nor does
there appear to be anything under the mail/message menus.  I've tried
all the command names I can think of but auto-complete never finds
anything.

I must be missing something obvious.

In mail or message mode, how do you increase/decrease the quote level
of a region?

-- 
Grant