Am an F1 student,sponsored by my father when I was applying to study in USA.After that three months of entry USA I lost my father by food poison.My uncle that I have in USA,married to my sister and he promised to sponsor me after paying the first tuition he said its too much for him and the family so he decided to file for permanent resident for me so that I will start paying school tuition by myself because am now his dependent.Is it possible?

He is not your parent... no, but your sister maybe. When she becomes US citizen, she can file for you but it takes more than 10 years and you should not wait for the visa in US.