Learn Turkish: Kurulu bilgilendirmeden önce raporu revize ediyor musunuz? - Are you revising the report before informing the board?

It is the direct object of the verbal action bilgilendirmeden (informing). In Turkish, even when a verb is turned into a gerund or a modifying phrase (like the -meden form here), it still requires the same case markers for its objects as the main verb would. Because you inform a specific entity, Kurul takes the definite accusative suffix -u.

Can we break down the layers of suffixes in bilgilendirmeden?

This word is a great example of Turkish agglutination! It starts with the noun bilgi (information). Adding -len creates the verb bilgilenmek (to become informed). The causative suffix -dir turns it into bilgilendirmek (to make informed / to inform someone). Finally, the -meden suffix is attached as part of the "before [verb]ing" structure.

Does the suffix -meden always need önce to mean "before"?

Yes, to explicitly mean "before doing something", you must use the full -meden önce (or -madan önce) structure. If you drop önce and just use the -meden suffix on a verb, the meaning changes entirely to "without doing something" (which would mean "without informing the board" in this context).

Why does revize need the helper verb etmek?