As we all know that due to the lapse in government funding, the NCBI's bankit service is also closed. Therefore, I was wondering Is there any alternative database to submit nucleotide sequences?
DDBJ is also an option: http://www.ddbj.nig.ac.jp/
This is what the NCBI site states: "Data exchange between DDBJ, EMBL and GenBank occurs daily so it is only necessary to submit the sequence to one database, whichever one is most convenient, without regard for where the sequence may be published".
I agree with Gustavo Acevedo-Hernandez and Gustavo Rodriguez-Esteban. NCBI, EBI and DDBJ has the policy of sharing the data and synchronizing the databases. Even if you submit to one of them eventually it ends up in all three. But it may take some time because of their individual curation process.