Application for a visa in the United Kingdom on dependents

Assuming that your mother sponsored your UAE visa as a resident and not as a financial sponsor, this should not be a problem. You can explain the specific circumstances in the "Additional Information" section at the end of the application and / or in your cover letter. Providing proof that your mother is dependent on you will help her, for example, her age, the evidence that she lives with you, proof that she gives you a regular subsidy, etc.

Recently he has been refused a Schengen visa. The Schengen visa from Greece was rejected and in that question it states that it does not have a previous travel history. That combination of circumstances may not be advantageous for your UK visa application.