TOKYO, March 6 (Reuters) - Japan's Nikkei share average rose on Tuesday and was poised to snap a four-day losing run after Wall Street shares rallied overnight, with the dollar's bounce lifting exporter shares.

The Nikkei was up 2.15 percent at 21,491.28 as of 0128 GMT.

The index had suffered four straight days of losses prior, with global risk sentiment hit after U.S. President Donald Trump proposed tariffs for imported steel and aluminium last week.

Equity markets rebounded, however, as fears of a global trade war ebbed somewhat on the back of rising expectations that Trump would back down from his tariff imposition.

Automakers, which are large consumers of steel and aluminium, bounced. Automakers are also major exporters and the dollar's rebound versus the yen provided extra support.

Honda Motor Co rose 2.4 percent, Toyota Motor Corp gained 1.7 percent and Subaru Corp climbed 1.4 percent.

Panasonic Corp gained 2.2 percent and Tokyo Electron added 3.5 percent.

Steel shares also rose, with Nippon Steel & Sumitomo Metal advancing 1.75 percent, JFE Holdings gaining 2.35 percent and Kobe Steel adding 0.9 percent.

The broader Topix was 1.77 percent higher at 1,724.75.

The dollar was at 106.325 yen, having recovered from a 15-month low of 105.240 plumbed on Friday. (Reporting by the Tokyo markets team; Editing by Simon Cameron-Moore)