Southern Essex Register of Deeds John L. O?Brien has, since last fall, been going after the nation?s largest banks like an attack dog that won?t loosen its bite on its target.The 59-year-old Lynn native claims the nation?s largest lenders have cheated the Southern Registry out of upward of $22 million in mortgage assignment recording fees and billions from public deeds registries throughout the country. And he?s hardly stewing over this quietly.O?Brien this month requested permission from state Treasurer Steve Grossman, and is awaiting the treasurer?s response, to pull all of the Southern Registry?s revenue – more than $25 million annually – out of Bank of America and into a bank not affiliated with the Virginia-based Mortgage Electronic Registration Systems Inc. (MERS).Last November, O?Brien sent a letter to state Attorney General Martha Coakley urging her office to investigate MERS for what O?Brien contends is the intentional hiding of mortgage transfers to avoid paying local assignment recording fees, which he says has corrupted the chain of title for potentially tens of thousands of properties.MERS is a private corporation established by a consortium of big banks, including Bank of America, in the late 1990s to act as a mortgage title holding company, or mortgagee, on all properties acquired by its member banks.As O?Brien sees it, MERS was created solely as a vehicle for the banks to avoid paying public mortgage assignment recording fees; the fee is $75 at the Southern Registry, $20 of which is earmarked for community preservation in cities and towns and another $5 for computer system upgrades at the registry.With the rapid-fire sale of bundled mortgages as securities in the decade leading up to the recession and housing market bust, many homeowners – including many foreclosed upon and many in the process of foreclosure – were left in the dark as to who held their mortgage.?I?ve been here 34 years and this is the first time during my tenure that if someone comes into my office to ask who owns their mortgage, I can?t give them an honest answer,” O?Brien said Friday. “The chain of title has been broken ? That?s why I?m taking a lead on this.”A spokeswoman for MERS, contacted by phone on Monday for comment, issued an email statement to the Item from Janis L. Smith, vice president of corporate communications for MERSCORP Inc.?Mr. O?Brien?s premise is unfounded,” Smith wrote. “As we have said before, all MERS mortgages are recorded in the public land records and MERS members pay recording fees when the mortgage is recorded ? The use of MERS is in compliance with the purpose and intent of the state recording acts.”A more lengthy response by MERS to the letter O?Brien wrote to Coakley was posted on MERS? company Web site last December, which states, “MERS pays recording fees when the mortgage is recorded. Fees are paid for a service performed, and if a document is eliminated because it is no longer necessary, no fee is due because there is nothing to record. In fact, MERS greatly reduces the workload of county recorders, resulting in lower operating expenses for the county recorder?s office.”The statement goes on to explain that if a mortgage is transferred from one MERS- member bank to another, MERS continues as the mortgagee and thus there is no need for a public mortgage assignment recording.O?Brien, meanwhile, is also vocal on alleged fraudulent foreclosure practices by banks, proof of which he said he has at the Southern Registry.O?Brien referred to a 60 Minutes segment the CBS news show aired on April 1, “Mortgage paperwork mess: Next housing shock?” in which it showed how a forgery mill was set up in Georgia to generate fraudulent paperwork to replace lost mortgage transfer documents as a means to establish the title holder. The mill, Doc X, hired people off the street to produce fraudulent paperwork for major banks including Wells Fargo, HSBC, Deutche Bank, Citibank, U.S. Bank and Bank of America, 60 Minutes reported. And