Brendan Dassey On the Move From One Prison to Another

1/21/2016 9:54 AM PST BY TMZ STAFF

0121-brendan-dassey-apBrendan Dassey has been quietly moved from one prison to another.

TMZ has learned Dassey -- the younger subject of Netflix's "Making A Murderer" -- was transferred Wednesday from Green Bay Correctional Institution to Columbia Correctional Institution ... a Wisconsin maximum security prison about 125 miles away.

A spokesperson for the Wisconsin Department of Corrections tells us inmate transfers are common ... but wouldn't elaborate. 

Sources close to Dassey tell us the move was for several reasons -- one of which related to the convict becoming so high profile as a result of "Making A Murderer."