Just verifying that there is no response either when you are using a standard USB cable. Is this correct?
Why did you apply 5V to the data lines?
Here is an image which shows how an OTG cable is wired if that is what you were trying to do. You apply an Earth (or Ground) to pin 4 in the cable end which plugs into the device.
(click on image to enlarge for better viewing.
Applying 5V to either of the data lines would definitely cause a problem.
I'm not entirely sure but the USB controller function could be incorporated into the main CPU IC on the motherboard. You might be lucky in that there may be components between the USB connector and the IC that may have been damaged and not the IC itself, but it may be difficult to find without a schematic diagram.
Also it would be easier to replace the motherboard than to try and replace the main IC if it is faulty.
Here is a link to the Ifixit guide on how to replace the motherboard
Nexus 7 Motherboard Replacement
Depending on your model version, here is a link to the ifixit's shop motherboard spare part. It is just shown to give you an idea of the price. It may be that it is the wrong motherboard for your tablet.
Nexus 7 (2nd Gen Wi-Fi) Motherboard
If it is the wrong one or that the price doesn't suit you, to find other suppliers search online for (insert your tablet model number) motherboard replacement part to get results that may suit you better.
Hi @yekta ,
Here is a link to the ifixit 1st Generation motherboard. (it says that it is the last one they have)
Nexus 7 (1st Gen Wi-Fi) Motherboard