I want to write some simple gene regulations in math mode in LaTeX. Activation is denoted with a normal arrow, so I can write `$A \rightarrow B$` for A activates B, but I'm failing to find an arrow with a straight-line head for repression. Is there some symbol/package that I can use to write something like `$A \repressionarrow B$` and obtain the following.

[![repression arrow](https://i.stack.imgur.com/yorSy.png)](https://i.stack.imgur.com/yorSy.png)